Synthesis of new chiral <i>N</i>-arylsulfonyl-1,3-oxazolidin-2-ones from α-amino acids

Ahmed Ould Aliyenne; Jamil Kraïem; Yakdhane Kacem; Béchir Ben Hassine

doi:10.1016/j.crci.2006.10.004

Synthesis of new chiral N-arylsulfonyl-1,3-oxazolidin-2-ones from α-amino acids

Ahmed Ould Aliyenne ¹ ; Jamil Kraïem ¹ ; Yakdhane Kacem ¹ ; Béchir Ben Hassine ¹

¹ Laboratoire de synthèse organique asymétrique et catalyse homogène, faculté des sciences de monastir, avenue de l'Environnement, 5019 Monastir, Tunisia

Comptes Rendus. Chimie, Volume 10 (2007) no. 3, pp. 251-258.

Résumés

Anglais
Français

A variety of new chiral N-arylsulfonyl-1,3-oxazolidin-2-ones were prepared in three steps starting from (d)- and (l)-amino acid. N-Arylsulfonyl amino alcohols, derived from amino acids, were carbonylated with the bis-(trichloromethyl) carbonate (BTC), in the presence of triethylamine, to provide optically pure N-phenylsulfonyloxazolidin-2-ones 3a–f, N-naphthylsulfonyloxazolidin-2-ones 3g–j and N-tosylsulfonyloxazolidin-2-ones 3k–p in good yields.

Re´sume´

Une variété de nouvelles N-arylsulfonyloxazolidin-2-ones chirales a été préparée en trois étapes à partir d'acides α-aminés (d) et (l). Les N-arylsulfonyl aminoalcools, dérivés des acides aminés, ont été carbonylés par l'intermédiaire du carbonate de bis-trichlorométhyle, avec de bons rendements chimiques.

Métadonnées

Reçu le : 2006-04-12
Accepté le : 2006-10-20
Publié le : 2006-12-20

DOI : 10.1016/j.crci.2006.10.004

Mots clés : Amino acids, Bis-(trichloromethyl)carbonate, N-Arylsulfonyloxazolidin-2-ones, Acides aminés, Carbonate de bis-trichlorométhyle, N-Arylsulfonyloxazolidin-2-ones

Affiliations des auteurs :

Ahmed Ould Aliyenne ¹ ; Jamil Kraïem ¹ ; Yakdhane Kacem ¹ ; Béchir Ben Hassine ¹

¹ Laboratoire de synthèse organique asymétrique et catalyse homogène, faculté des sciences de monastir, avenue de l'Environnement, 5019 Monastir, Tunisia

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     author = {Ahmed Ould Aliyenne and Jamil Kra{\"\i}em and Yakdhane Kacem and B\'echir Ben Hassine},
     title = {Synthesis of new chiral {\protect\emph{N}-arylsulfonyl-1,3-oxazolidin-2-ones} from \ensuremath{\alpha}-amino acids},
     journal = {Comptes Rendus. Chimie},
     pages = {251--258},
     publisher = {Elsevier},
     volume = {10},
     number = {3},
     year = {2007},
     doi = {10.1016/j.crci.2006.10.004},
     language = {en},
}

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Ahmed Ould Aliyenne; Jamil Kraïem; Yakdhane Kacem; Béchir Ben Hassine. Synthesis of new chiral N-arylsulfonyl-1,3-oxazolidin-2-ones from α-amino acids. Comptes Rendus. Chimie, Volume 10 (2007) no. 3, pp. 251-258. doi : 10.1016/j.crci.2006.10.004. https://comptes-rendus.academie-sciences.fr/chimie/articles/10.1016/j.crci.2006.10.004/

Version originale du texte intégral

1 Introduction

1,3-Oxazolidin-2-ones are structural components of many compounds that display pharmacological properties [1–11]. Furthermore, they have also been used as chiral auxiliaries and intermediates in asymmetric synthesis of numerous pharmaceutical products [12,13].

During the past few years, significant progress has been made in the discovery of new biologically active N-aryl and N-alkyloxazolidin-2-ones [14–16]. However, the N-sulfonylated oxazolidin-2-ones were not sufficiently elaborated, and only few reports have described the synthesis of N-tosyloxazolidin-2-ones [17–19].

Several methods have been employed for the synthesis of racemic and optically active oxazolidin-2-ones. One of the most efficient methods to build the heterocyclic carbamate involves the condensation of 1,2-amino alcohols with carbonyl derivatives such as phosgene [20], trichloromethyl chloroformate [18], bis-(trichloromethyl) carbonate [21], isocyanates [12], chloroformates [22], ureas [23], or diethylcarbonate [24]. The catalyzed addition of CO₂ to aziridines has also been employed to prepare racemic N-tosyloxazolidin-2-ones [17].

Izuhara et al. [18] have described a four-step synthesis of the optically pure 4-benzyl-3-tosyloxazolidin-2-one starting from (l)-phenylalanine. In this sequence, the trichloromethyl chloroformate has been employed as a carbonylating agent. In this work, we describe a three-step synthesis of a variety of new chiral N-arylsulfonyloxazolidin-2-ones, using the same strategy cited above. We have employed the bis-(trichloromethyl) carbonate (BTC) instead of the trichloromethyl chloroformate, since it appears to be safer due to its lower vapor pressure and higher stability [25].

2 Results and discussion

Enantiomerically pure N-arylsulfonyloxazolidin-2-ones are prepared in three steps from commercially available (d)- and (l)-amino acid. As illustrated in Scheme 1, sulfonylation of α-amino acids with arylsulfonylchlorides, in a two-phase mixture of i-PrNEt₂ in acetone and aqueous NaOH, leads to the N-arylsulfonyl amino acids 1a–p, which were then reduced to the N-arylsulfonyl amino alcohols 2a–p with good to excellent yields (Table 1) by use of lithium aluminium hydride in THF or (THF:Et₂O). The same procedure has been employed by Berry and Craig [26] to prepare N-tosyl-α-amino alcohols from α-amino acids. These authors have determined the enantiomeric purity of N-tosyl-α-amino alcohols (entry 2m–p) by the formation of the corresponding MTPA esters [27], the minor diastereoisomers have not been detected in the 500 MHz ¹H NMR spectrum of the crude product [26].

Scheme 1
Synthesis of N-arylsulfonyl-α-amino alcohols.

Entry	R	Ar	Config.	[α]_D	m.p. (°C)	Yields (%)
2a	i-Pr	C₆H₅–	S	−10	76–78	98
2b	Me	C₆H₅–	S	+15	Oil	97
2c	i-Bu	C₆H₅–	S	+18	102–104	99
2d	Ph	C₆H₅–	R	−10	114–116	98
2e	Bn	C₆H₅–	S	+18.7	64–66	95
2f	s-Bu	C₆H₅–	S	+25	58–60	99
2g	Me	2-Naphthyl	S	+23	82–84	82
2h	i-Pr	2-Naphthyl	S	−10	96–98	86
2i	s-Bu	2-Naphthyl	S	+18	112–114	85
2j	Bn	2-Naphthyl	S	+22	106–108	75
2k	s-Bu	p-H₃C–C₆H₄–	S	−15	80–81	98
2l	Ph	p-H₃C–C₆H₄–	R	−10	93–94	97
2m	i-Pr	p-H₃C–C₆H₄–	S	+16.8	88–89	98 (99)^a
2n	i-Bu	p-H₃C–C₆H₄–	S	+23.7	105–106	96 (98)^a
2o	Bn	p-H₃C–C₆H₄–	S	−15	74–75	97 (99)^a
2p	Me	p-H₃C–C₆H₄–	S	+15.8	57–58	98 (100)^a

^a Chemical yields 2m–p reported by Berry and Craig [26].

As far as we know, compounds 2a–l were prepared for the first time during this study. Compounds 2m–p were prepared by Barry and Craig [26].

Subsequent reaction of compounds 2a–p with BTC, in the presence of Et₃N at −78 °C to r.t., provided the corresponding N-arylsulfonyloxazolidin-2-ones 3a–p in excellent yields without racemization, as confirmed by chiral HPLC analysis on tow compounds (entries 3c and 3h) (Scheme 2).

Scheme 2
Synthesis of N-arylsulfonyloxazolidin-2-ones.

In Table 2, are given the chemical yields and the physical properties of compounds 3a–p, which have not been reported to date, except compound 3p.

Entry	R	Ar	Config.	m.p. (°C)	[α]_D	Yields (%)
3a	Bn	C₆H₅−	S	107–109	+38.3	96
3b	i-Pr	C₆H₅–	S	99–101	+56.8	95
3c	Me	C₆H₅–	S	60–62	+45.0	95
3d	i-Bu	C₆H₅–	S	139–141	+39.6	96
3e	Ph	C₆H₅–	R	118–120	−13.6	97
3f	s-Bu	C₆H₅–	S	144–146	+60.0	95
3g	Me	2-Naphthyl	S	129–131	+40.1	88
3h	i-Pr	2-Naphthyl	S	141–143	+16.7	85
3i	s-Bu	2-Naphthyl	S	130–132	+60.0	81
3j	Bn	2-Naphthyl	S	126–128	+71.4	79
3k	i-Pr	p-H₃C–C₆H₄–	S	115–118	+58.2	95
3l	i-Bu	p-H₃C–C₆H₄–	S	151–153	+38.4	96
3m	s-Bu	p-H₃C–C₆H₄–	S	170–172	+41.0	95
3n	Me	p-H₃C–C₆H₄–	S	117–119	+52.2	97
3o	Ph	p-H₃C–C₆H₄–	R	149–151	−39.5	95
3p	Bn	p-H₃C–C₆H₄–	S	136–138	+36.2	96

3 Conclusion

We have synthesized, in good yields, a variety of new chiral N-arylsulfonyloxazolidin-2-ones from their corresponding α-amino acids. The test of the biological activity and the study of synthetic properties of these new products are under investigation in our laboratory.

4 Experimental section

TLC was performed on Merck 60F-254 silica gel plates (layer thickness 0.25 mm). Column chromatography was performed on silica gel (70–230 mesh) using ethylacetate and cyclohexane mixture as eluents. Melting points were determined on a Electrothermal 9002 apparatus and are uncorrected. ¹H NMR spectra were recorded at 300 MHz. All chemical shifts are reported as δ values (ppm) relative to internal tetramethylsilane. CH₂Cl₂, THF were respectively distilled over CaH₂ and Na/benzophenone. Elemental analyses were carried out by ‘Service de microanalyse’ of ‘Institut national de recherche et d'analyse physico-chimique de Tunis’. HPLC analyses were conducted on a methanol/hexane [70:30] system with a UV detector at 254 nm, using a Chirobiotic V column (250 × 46 mm) and a flow rate of 0.6 mL/min.

N-Arylsulfonyl amino alcohols 2a–p were prepared according to literature [26]; compounds 2m–p were reported by Berry and Craig [26].

4.1 (2S)-N-(Phenylsulfonyl)valinol: 2a

Yield = 98%; m.p.: 76–78 °C [hexane:ethylacetate (90:10)]. IR (cm⁻¹): ν_NH = 3215, ν_OH = 3493; [α]_D = −10 (c = 1, CHCl₃). ¹H NMR (300 MHz, CDCl₃): 0.70–0.79 (2d, 6H); 1.73–1.82 (m, 1H); 2.22 (s, 1H); 3.03–3.09 (m, 1H); 3.54–361 (m, 2H); 5.24 (d, 1H); 7.28–7.60 (m, 3H); 7.92 (d, 1H). ¹³C NMR (75 MHz, CDCl₃): (18.80, 19.49, 2CH₃–); (29.83, –CH–); (61.48, CH–NH–); (63.41, –CH₂–O–); (127.49–140.93, C_arom). Anal. calc. for C₁₁H₁₇NO₃S (243.32): C, 54.30; H, 7.04; N, 5.76. Found: C, 54.20; H, 7.20; N, 5.72.

4.2 (2S)-N-(Phenylsulfonyl)alaninol: 2b

Yield = 97%; oil; [α]_D = +15 (c = 0.6, CHCl₃). IR (cm⁻¹): ν_NH = 3217, ν_OH = 3477. ¹H NMR (300 MHz, CDCl₃): 0.98 (d, 3H); 3.01–3.06 (m, 1H); 3.08 (s, 1H); 3.37–3.58 (m, 3H); 5.75 (s, 1H); 7.48–7.60 (m, 3H); 7.91 (d, 2H). ¹³C NMR (75 MHz, CDCl₃): (17.28, 1CH₃–); (51.91, –CH–NH–); (66.47, –CH₂–O–); (127.35 and 141.01, C_arom). Anal. calc. for C₉H₁₃NO₃S (215.27): C, 50.22; H, 6.09; N, 6.51. Found: C, 50.10; H, 6.10; N, 6.42.

4.3 (2S)-N-(Phenylsulfonyl)leucinol: 2c

Yield = 99%; m.p.: 102–104 °C [hexane:ethylacetate (90:10)]; [α]_D = +18 (c = 1, CHCl₃). IR (cm⁻¹): ν_NH = 3201, ν_OH = 3397. ¹H NMR (300 MHz, CDCl₃): 0.61–0.68 (2d, 6H); 1.22–1.51 (m, 2H); 3.02 (s, 1H); 3.17–3.56 (m, 3H); 5.25 (d, 1H); 7.30–7.53 (m, 3H); 7.86 (d, 2H). ¹³C NMR (75 MHz, CDCl₃): (20.24, 22.30, 2CH₃–); (38.75, –CH₂–); (51.72, CH–NH–); (64.92, –CH₂–O–); (126.48–140.25, C_arom). Anal. calc. for C₁₂H₁₉NO₃S (257.35): C, 56.01; H, 7.44; N, 5.44. Found: C, 55.80; H, 7.42; N, 5.39.

4.4 (2S)-N-(Phenylsulfonyl)phenylglycinol: 2d

Yield = 98%; m.p.: 114–116 °C [hexane:ethylacetate (90:10)]; [α]_D = −10 (c = 0.5, CHCl₃). IR (cm⁻¹): ν_NH = 3302, ν_OH = 3477. ¹H NMR (300 MHz, CDCl₃): 3.35 (s, 1H); 3.72–3.75 (m, 2H); 4.07–4.59 (m, 1H); 6.25 (d, 1H); 7.04–7.37 (m, 10H). ¹³C NMR (75 MHz, CDCl₃): (60.23, CH–NH–); (66.49, –CH₂–O–); (126.76–140.56, C_arom). Anal. calc. for C₁₄H₁₅NO₃S (277.34): C, 60.63; H, 5.45; N, 5.05. Found: C, 60.53; H, 5.42; N, 5.10.

4.5 (2S)-N-(Phenylsulfonyl)phenylalaninol: 2e

Yield = 95%; m.p.: 64–66 °C [hexane:ethylacetate (90:10)]; [α]_D = +18.7 (c = 0.5, CHCl₃). IR (cm⁻¹): ν_NH = 3193, ν_OH = 3416. ¹H NMR (300 MHz, CDCl₃): 2.64–2.83 (dd, 2H); 3.46–3.70 (m, 3H); 5.40 (d, 1H); 6.90–7.73 (m, 10H). ¹³C NMR (75 MHz, CDCl₃): (38.10, –CH₂–); (57.22, –CH–NH–); (64.36, –CH₂–O–); (126.76–140.30, C_arom). Anal. calc. for C₁₅H₁₇NO₃S (291.36): C, 61.83; H, 5.88; N, 4.81. Found: C, 61.72; H, 5.80; N, 5.80.

4.6 (2S, 3S)-N-(Phenylsulfonyl)isoleucinol: 2f

Yield = 99%; m.p.: 58–60 °C [hexane:ethylacetate (90:10)]; [α]_D = +25 (c = 0.6, CHCl₃). IR (cm⁻¹): ν_NH = 3216, ν_OH = 3408. ¹H NMR (300 MHz, CDCl₃): 0.69 (d, 3H); 0.86 (t, 3H); 1.02 (m, 2H); 1.41–1.52 (m, 2H); 2.35 (s, 1H); 3.15–3.24 (m, 1H); 3.52–3.54 (m, 2H); 5.09 (d, 1H); 7.23–7.51 (m, 3H); 7.86 (d, 2H). ¹³C NMR (75 MHz, CDCl₃): (13.24, 22.91, 2CH₃–); (25.39, 35.27, 2-CH–); (60, CH–NH–); (60.65, –CH₂–O–); (127.34–142.58, C_arom). Anal. calc. for C₁₂H₁₉NO₃S (257.35): C, 56.01; H, 7.44; N, 5.44. Found: C, 56.10; H, 7.52; N, 5.42.

4.7 (2S)-N-(2-Naphthylsulfonyl)alaninol: 2g

Yield = 82%; m.p.: 82–84 °C [hexane:ethylacetate (90:10)]; [α]_D = +23 (c = 1, CHCl₃). IR (cm⁻¹): ν_NH = 3175, ν_OH = 3327. ¹H NMR (300 MHz, DMSO): 1.81 (d, 3H); 2.21 (s, 1H); 3.72–4.64 (m, 3H); 5.64 (s, 1H); 7.58–7.81 (m, 2H); 7.90–8.18 (m, 4H); 8.69 (s, 1H). ¹³C NMR (75 MHz, DMSO): (20.11, CH₃–); (56.86, CH–NH–); (70.89, –CH₂–O–); (119.73–13251, C_arom).

4.8 (2S)-N-(2-Naphthylsulfonyl)valinol: 2h

Yield = 85%; m.p.: 96–98 °C [hexane:ethylacetate (90:10)]; [α]_D = −10 (c = 1, CHCl₃). IR (cm⁻¹): ν_NH = 3187, ν_OH = 3491. ¹H NMR (300 MHz, DMSO): 0.61–0.89 (2d, 6H); 2.05 (s, 1H); 3.89–4.51 (m, 3H); 5.82 (d, 1H); 7.60–7.73 (m, 2H); 7.89–8.05 (m, 4H); 8.54 (s, 1H). ¹³C NMR (75 MHz, DMSO): (16.27, 20.07, 2CH₃–); (30.10, –CH–); (61.20, CH–NH–); (66.92, –CH₂–O–); (120.12–1139.75, C_arom). Anal. calc. for C₁₅H₁₉NO₃S (293.38): C, 61.41; H, 6.53; N, 4.77. Found: C, 60.80; H, 7.10; N, 4.62.

4.9 (2S, 3S)-N-(2-Naphthylsulfonyl)isoleucinol: 2i

Yield = 86%; m.p.: 112–114 °C [hexane:ethylacetate (90:10)]; [α]_D = +18 (c = 1, CHCl₃). IR (cm⁻¹): ν_NH = 3217, ν_OH = 3512. ¹H NMR (300 MHz, DMSO): 0.81 (d, 3H); 0.83–0.99 (t, 3H); 1.24–1.42 (m, 2H); 1.57–2.74 (m, 1H); 2.18 (s, 1H); 3.86–4.29 (m, 3H); 5.71 (d, 1H); 7.18–7.41 (m, 2H); 7.68–8.27 (m, 4H); 8.83 (s, 1H). ¹³C NMR (75 MHz, DMSO): (1125, 13.08, 2CH₃–); (26.24, –CH–) (36.18, –CH₂–); (60.64, CH–NH–); (66.71, –CH₂–O–); (122.08–139.16, C_arom).

4.10 (2S)-N-(2-Naphthylsulfonyl)phenylalaninol: 2j

Yield = 75%; m.p.: 106–108 °C [hexane:ethylacetate (90:10)]; [α]_D = +22 (c = 1, CHCl₃). IR (cm⁻¹): ν_NH = 3211, ν_OH = 3519. ¹H NMR (300 MHz, DMSO): 2.09 (s, 1H); 2.82–2.89 (m, 1H); 3.41–3.48 (m, 1H); 3.98–4.12 (m, 2H); 4.57–4.62 (m, 1H); 5.75 (d, 1H); 7.21–7.45 (m, 5H); 7.62–7.74 (m, 2H); 8.01–8.16 (m, 4H); 8.74 (s, 1H). ¹³C NMR (75 MHz, DMSO): (40.21, –CH₂–); (57.51, CH–N–); (67.95, –CH₂–O–); (121.75–136.93, C_arom).

4.11 (2S)-N-(4-Methylbenzenesulfonyl)isoleucinol: 2k

Yield = 98%; m.p.: 80–81 °C [hexane:ethylacetate (90:10)]; [α]_D = −15 (c = 1, CHCl₃). IR (cm⁻¹): ν_NH = 3300, ν_OH = 3481. ¹H NMR (300 MHz, CDCl₃): 0.75 (d, 3H); (t, 3H); 0.91 (m, 2H); 1.35–1.49 (m, 2H); 2.2 (s, 1H); 2.42 (s, 3H); 3.09–3.13 (m, 1H); 3.55–3.56 (m, 2H); 5.1 (d, 1H); 7.28–7.79 (AA′BB′, 4H). ¹³C NMR (75 MHz, CDCl₃): (11.72–21.91, 3CH₃–); (25.60, 36.75, 2-CH–); (60.11 and 60.78, CH–NH–, –CH₂–O–); (127.12–143.50, C_arom). MS: C₁₃H₂₁NSO₃; MW = 271 g/mol; m/z = 240 (C₁₁H₁₈NSO₃⁺, 51%); m/z = 155 (C₇H₇SO₂⁺, 67%); m/z = 91 (C₇H₇⁺, 100%).

4.12 (2S)-N-(4-Methylbenzenesulfonyl)phenylglycinol: 2l

Yield = 97%; m.p.: 93–94 °C [hexane:ethylacetate (90:10)]; [α]_D = −10 (c = 1, CHCl₃). IR (cm⁻¹): ν_NH = 3319, ν_OH = 3396. ¹H NMR (300 MHz, CDCl₃): 2.4 (s, 3H); 2.68–2.76 (dd, 2H); 3.49–3.65 (m, 3H); 5.15 (d, 1H); 6.95–7.58 (m, 9H). ¹³C NMR (75 MHz, CDCl₃): (21.61, CH₃–); (61.24, CH–NH–); (67.08, –CH₂–O–); (126.67–141.27, C_arom). MS: C₁₃H₂₁NSO₃; MW = 305 g/mol; m/z = 274 (C₁₄H₁₆NSO₃⁺, 8%); m/z = 214 (C₇H₉NSO₃⁺, 38%); m/z = 155 (C₇H₇SO₂⁺, 50%); m/z = 91 (C₇H₇⁺, 100%).

4.13 Preparation of (4S)-3-(phenylsulfonyl)-4-benzyloxazolidin-2-one: 3a

To a solution of bis-(trichloromethyl)carbonate (0.43 g, 1.44 mmol, 0.3 eq) in CH₂Cl₂ (20 mL) at −78 °C was slowly added a solution of N-(phenylsulfonyl)phenylalaninol 2e (1.07 g, 3.68 mmol) in CH₂Cl₂ (40 mL). After 15 min of stirring, triethylamine (10 mmol, 1.4 mL, 3 eq) in CH₂Cl₂ (80 mL) was added dropwise maintaining the temperature below −70 °C. The resulting mixture was stirred at −78 °C for 5 min and then the ethylacetate–N₂ (liquid) bath was removed. The reaction mixture was stirred at room temperature for 2 h and washed with 1 N HCl (50 mL) and brine (3 × 25). Evaporation of the solvent under reduced pressure gave a residue, which was purified by chromatography on silica gel using [cyclohexane/ethylacetate (8:2)], as mobile phase.

Yield = 96%; m.p.: 107–109 °C [hexane:ethylacetate (90:10)]; [α]_D = +38.3 (c = 1, CHCl₃). IR (cm⁻¹): ν_CO = 1772. ¹H NMR (300 MHz, CDCl₃): 2.83–2.88 (m, 1H); 3.49–3.55 (m, 1H); 4.11–4.20 (m, 2H); 4.65–4.73 (m, 1H); 7.02–7.70 (m, 10H). ¹³C NMR (75 MHz, CDCl₃): (40.13, –CH₂–); (58.41, CH–N–); (67.06, –CH₂–O–); (127.99–138.48, C_arom); (152.38, CO). MS: C₁₆H₁₅NO₄S; MW = 317 g/mol; m/z = 253 (C₁₆H₁₅NO₂⁺, 64%); m/z = 141 (C₆H₅O₂S⁺, 81%); m/z = 91 (C₇H₇⁺, 100%); m/z = 77 (C₆H₅⁺, 43%). Anal. calc. for C₁₆H₁₅NO₄S (317.36): C, 60.55; H, 4.76; N, 4.41. Found: C, 60.10; H, 4.32; N, 4.20.

4.14 (4S)-3-(Phenylsulfonyl)-4-i-propyloxazolidin-2-one: 3b

Compound 3b (90:10); [α]_D = +58.8 (c = 0.5, CHCl₃). IR (cm⁻¹): ν_CO = 1761. ¹H NMR (300 MHz, CDCl₃): 0.70–0.94 (2d, 6H); 2.41–2.52 (m, 1H); 4.14–4.48 (m, 3H); 7.54–8.11 (m, 5H). ¹³C NMR (75 MHz, CDCl₃): (14.30, 18.16, 30.24, 3CH₃–); (62.08, CH–NH–); (63.90, –CH₂–O–); (128.74–138.46, C_arom); (152.79, CO). MS: C₁₂H₁₅NO₄S; MW = 269 g/mol; m/z = 226 (C₉H₈NO₄S⁺, 38%); m/z = 205 (C₁₂H₁₅NO₂⁺, 12%); m/z = 176 (C₉H₈NO₂⁺, 31%); m/z = 141 (C₇H₇SO₂⁺, 100%); m/z = 77 (C₆H₅⁺, 67%). Anal. calc. for C₁₂H₁₅NO₄S (269.32): C, 53.52; H, 5.61; N, 5.20. Found: C, 53.40; H, 5.52; N, 5.13.

4.15 (4S)-3-(Phenylsulfonyl)-4-methyloxazolidin-2-one: 3c

Yield = 95%; m.p.: 60–62 °C [hexane:ethylacetate (90:10)]; [α]_D = +45 (c = 1, CHCl₃). IR (cm⁻¹): ν_CO = 1761. ¹H NMR (300 MHz, CDCl₃): 1.48 (d, 3H); 3.87–3.91 (m, 1H); 4.37–4.56 (m, 2H); 7.50–8.03 (m, 5H). ¹³C NMR (75 MHz, CDCl₃): (20.66, CH₃–); (53.71, CH–NH–); (69.70, –CH₂–O–); (128.31–138.05, C_arom); (152.17, CO). MS: C₁₀H₁₁NO₄S; MW = 241 g/mol; m/z = 241 M⁺, 7%); m/z = 226 (C₉H₈NO₄S⁺, 30%); m/z = 177 (C₁₀H₁₁NO₂⁺, 55%); m/z = 141 (C₆H₅SO₂⁺, 100%); m/z = 77 (C₆H₅⁺, 57%). Anal. calc. for C₁₀H₁₁NO₄S (241.26): C, 49.78; H, 4.60; N, 5.81. Found: C, 49.72; H, 4.53; N, 5.60.

Enantiomeric purity of 3c was determined by HPLC analyses on Chirobiotic V column (250 × 46 mm) with a flow rate of 0.6 mL/min. Mobile phase methanol/hexane [70:30]; retention times: (4S)-3-(phenylsulfonyl)-4-methyloxazolidin-2-one 10.4 min; (4R)-3-(phenylsulfonyl)-4-methyloxazolidin-2-one 15.2 min.

4.16 (4S)-3-(Phenylsulfonyl)-4-i-butyloxazolidin-2-one: 3d

Yield = 96%; m.p.: 139–141 °C [hexane:ethylacetate (90:10)]; [α]_D = +39.6 (c = 0.5, CHCl₃). IR (cm⁻¹): ν_CO = 1770. ¹H NMR (300 MHz, CDCl₃): 0.90–1.05 (m, 6H); 1.56–1.67 (m, 2H); 1.94–2.04 (m, 1H); 4.05–4.09 (m, 1H); 4.36–452 (m, 2H); 7.54–8.08 (m, 5H). ¹³C NMR (75 MHz, CDCl₃): (21.44, 23.61, 24.67, 3CH₃–); (42.87, –CH₂–); (56.27, CH–NH–); (68.15, –CH₂–O–); (128.41–138.21, C_arom); (152, CO). MS: C₁₃H₁₇NO₄S; MW = 283 g/mol; m/z = 219 (C₁₃H₁₇NO₂⁺, 13%); m/z = 162 (C₉H₈NO₂⁺, 24%); m/z = 141 (C₆H₅SO₂⁺, 100%); m/z = 77 (C₆H₅⁺, 67%). Anal. calc. for C₁₃H₁₇NO₄S (283.34): C, 55.11; H, 6.05; N, 494. Found: C, 55.01; H, 6.17; N, 4.83.

4.17 (4R)-3-(Phenylsulfonyl)-4-phenyloxazolidin-2-one: 3e

Yield = 97%; m.p.: 118–120 °C [hexane:ethylacetate (90:10)]; [α]_D = −13.6 (c = 1, CHCl₃). IR (cm⁻¹): ν_CO = 1775. ¹H NMR (300 MHz, CDCl₃): 4.27–4.31 (m, 1H); 4.71–4.77 (t, 1H); 5.42–5.46 (m, 1H); 7.19–7.55 (m, 10H). ¹³C NMR (75 MHz, CDCl₃): (60.41, CH–NH–); (70.51, –CH₂–O–); (127.12–137.68, C_arom); (152.02, CO). MS: C₁₅H₁₃NO₄S; MW = 303 g/mol; m/z = 239 (C₁₅H₁₃O₂N⁺, 65%); m/z = 141 (C₆H₅O₂S⁺, 100%); m/z = 77 (C₆H₅⁺, 58%). Anal. calc. for C₁₅H₁₃NO₄S (303.33): C, 59.40; H, 4.32; N, 4.62. Found: C, 59.20; H, 4.21; N, 4.65.

4.18 (4S)-3-(Phenylsulfonyl)-4-[(1′S)-1′-methylpropyl]oxazolidin-2-one: 3f

Yield = 95%; m.p.: 144–146 °C [hexane:ethylacetate (90:10)]; [α]_D = 60 (c = 1, CHCl₃). IR (cm⁻¹): ν_CO = 1772. ¹H NMR (300 MHz, CDCl₃): 0.72 (d, 3H); 0.96–1.00 (t, 3H); 1.09–1.34 (m, 2H); 2.22 (m, 1H); 4.12–4.16 (m, 1H); 4.25–4.31 (t, 1H); 4.53–4.56 (m, 1H); 7.55–8.11 (m, 5H). ¹³C NMR (75 MHz, CDCl₃): (11.68, 12.19, 2CH₃–); (25.65, –CH–); (37.05, –CH₂–); (61.05, CH–NH–); (63.94, –CH₂–O–); (128.76–138.40, C_arom); (152.87, CO). MS: C₁₃H₁₇NO₄S; MW = 283 g/mol; m/z = 219 (C₁₃H₁₇NO₂⁺, 17%); m/z = 226 (C₉H₈NO₄S⁺, 15%); m/z = 141 (C₆H₅SO₂⁺, 100%); m/z = 77 (C₆H₅⁺, 63%). Anal. calc. for C₁₃H₁₇NO₄S (283.34): C, 55.11; H, 6.05; N, 4.94. Found: C, 55.10; H, 5.76; N, 4.80.

4.19 (4S)-3-(2-Naphthylsulfonyl)-4-methyloxazolidin-2-one: 3g

Yield = 88%; m.p.: 129–131 °C [hexane:ethylacetate (90:10)]; [α]_D = +40.1 (c = 0.5, CHCl₃). IR (cm⁻¹): ν_CO = 1762. ¹H NMR (300 MHz, CDCl₃): 1.59 (d, 3H); 3.93–4.66 (m, 3H); 7.62–7.73 (m, 2H); 7.92–8.05 (m, 4H); 8.68 (s, 1H). ¹³C NMR (75 MHz, CDCl₃): (21.19, CH₃–); (54.04, CH–NH–); (69.96, –CH₂–O–); (122.94–135.94, C_arom); (152.47, CO). MS: C₁₄H₁₃NO₄S; MW = 291 g/mol; m/z = 291 (M⁺, 13%); m/z = 227 (C₁₄H₁₃NO₂⁺, 35%); m/z = 168 (C₁₂H₁₀N⁺, 26%); m/z = 127 (C₁₀H₇⁺, 100%). Anal. calc. for C₁₄H₁₃NO₄S (291.32): C, 57.72; H, 4.50; N, 4.81. Found: C, 57.62; H, 4.41; N, 4.62.

4.20 (4S)-3-(2-Naphthylsulfonyl)-4-i-propyloxazolidin-2-one: 3h

Yield = 85%; m.p.: 141–143 °C [hexane:ethylacetate (90:10)]; [α]_D = +16.7 (c = 0.5, CHCl₃). IR (cm⁻¹): ν_CO = 1766. ¹H NMR (300 MHz, CDCl₃): 0.74–0.97 (2d, 6H); 4.14–4.53 (m, 3H); 7.61–7.72 (m, 2H); 7.91–8.02 (m, 4H); 8.68 (s, 1H). ¹³C NMR (75 MHz, CDCl₃): (14.39, 18.17, 2CH₃–); (30.13, –CH–); (62.14, CH–NH–); (63.94, –CH₂–O–); (122.57–135.91, C_arom); (152.87, CO). MS: C₁₇H₁₉NO₄S; MW = 333 g/mol; m/z = 319 (M⁺, 11%); m/z = 212 (C₁₃H₁₀NO₂⁺, 31%); m/z = 191 (C₁₀H₇NO₂S⁺, 52%); m/z = 127 (C₁₀H₇⁺, 100%). Anal. calc. for C₁₆H₁₇NO₄S (319.38): C, 60.17; H, 5.37; N, 4.39. Found: C, 59.95; H, 5.11; N, 4.44.

Enantiomeric purity of 3c was determined by HPLC analyses on Chirobiotic V column (250 × 46 mm) with a flow rate of 0.6 mL/min. Mobile phase methanol/hexane [70:30]; retention times: (4S)-3-(2-naphthylsulfonyl)-4-i-propyloxazolidin-2-one 11.2 min; (4R)-3-(2-naphthylsulfonyl)-4-i-propyloxazolidin-2-one 13.3 min.

4.21 (4S)-3-(2-Naphthylsulfonyl)-4-[(1′S)-1′-methylpropyl]oxazolidin-2-one: 3i

Yield = 87%; m.p.: 130–132 °C [hexane:ethylacetate (90:10)]; [α]_D = +60 (c = 1, CHCl₃). IR (cm⁻¹): ν_CO = 1776. ¹H NMR (300 MHz, CDCl₃): 0.74 (d, 3H); 0.98–1.02 (t, 3H); 1.16–1.37 (m, 2H); 2.04–2.17 (m, 1H); 4.13–4.61 (m, 3H); 7.12–7.15 (m, 2H); 7.62–8.05 (m, 4H); 8.69 (s, 1H). ¹³C NMR (75 MHz, CDCl₃): (11.75, 12.11, 2CH₃–); (25.68, –CH–); (37.20, –CH₂–); (61.11, CH–NH–); (63.94, –CH₂–O–); (122.93–135.91, C_arom); (152.93, CO). MS: C₁₇H₁₉NO₄S; MW = 333 g/mol; m/z = 333 (M⁺, 7%); m/z = 212 (C₁₃H₁₀NO₂⁺, 23%); m/z = 191 (C₁₀H₇NO₂S⁺, 64%); m/z = 127 (C₁₀H₇⁺, 100%). Anal. calc. for C₁₇H₁₉NO₄S (333.40): C, 61.24; H, 5.74; N, 4.20. Found: C, 61.20; H, 5.72; N, 4.10.

4.22 (4S)-3-(2-Naphthylsulfonyl)-4-benzyloxazolidin-2-one: 3j

Yield = 79%; m.p.: 107–109 °C [hexane:ethylacetate (90:10)]; [α]_D = +71.4 (c = 0.5, CHCl₃). IR (cm⁻¹): ν_CO = 1773. ¹H NMR (300 MHz, CDCl₃): 2.84–2.93 (m, 1H); 3.57–3.63 (m, 1H); 4.10–4.27 (m, 2H); 4.71–4.80 (m, 1H); 7.15–7.39 (m, 5H); 7.64–7.75 (m, 2H); 7.95–8.11 (m, 4H); 8.74 (s, 1H). ¹³C NMR (75 MHz, CDCl₃): (40.26, –CH₂–); (58.49, CH–N–); (67.05, –CH₂–O–); (122.95–135.99, C_arom); (152.42, CO). MS: C₁₇H₁₉NO₄S; MW = 367 g/mol; m/z = 212 (C₁₃H₁₀NO₂⁺, 15%); m/z = 191 (C₁₀H₇NO₂S⁺, 72%); m/z = 127 (C₁₀H₇⁺, 100%); m/z = 91 (C₇H₇⁺, 100%). Anal. calc. for C₂₀H₁₇NO₄S (367.42): C, 65.38; H, 4.66; N, 3.81. Found: C, 65.32; H, 4.62; N, 3.82.

4.23 (4S)-3-(4-Methylbenzenesulfonyl)-4-i-propyloxazolidin-2-one: 3k

Yield = 95%; m.p.: 115–117 °C [hexane:ethylacetate (90:10)]; [α]_D = +58.2 (c = 0.5, CHCl₃). IR (cm⁻¹): ν_CO = 1770. ¹H NMR (300 MHz, CDCl₃): 0.72–0.92 (2d, 6H); 2.43 (s, 3H); 4.12–4.45 (m, 3H); 7.32–7.96 (AA′BB′, 4H). ¹³C NMR (75 MHz, CDCl₃): (14.3–22, 3CH₃–); (30.26, –CH–); (62.05, CH–NH–); (63.91, –CH₂–O–); (128.7–147.9, C_arom); (152.8, CO). MS: C₁₃H₁₇NSO₄; MW = 283 g/mol; m/z = 240 (C₁₀H₁₀NSO₄⁺, 13%); m/z = 219 (C₁₃H₁₇NO₂⁺, 13%); m/z = 176 (C₁₀H₁₀NO₂⁺, 33%); m/z = 155 (C₇H₇SO₂⁺, 100%); m/z = 91 (C₇H₇⁺, 88%). Anal. calc. for C₁₃H₁₇NO₄S (283.34): C, 55.11; H, 6.05; N, 4.94. Found: C, 55.40; H, 5.80; N, 4.70.

4.24 (4S)-3-(4-Methylbenzenesulfonyl)-4-i-butyloxazolidin-2-one: 3l

Yield = 96%; m.p.: 151–153 °C [hexane:ethylacetate (90:10)]; [α]_D = +38.4 (c = 0.5 CHCl₃). IR (cm⁻¹): ν_CO = 1768. ¹H NMR (300 MHz, CDCl₃): 0.95–0.98 (m, 6H); 1.58–1.64 (m, 2H); 1.97 (m, 1H); 2.43 (s, 3H); 4.03–4.45 (m, 3H); 7.33–7.95 (AA′BB′, 4H). ¹³C NMR (75 MHz, CDCl₃): (21.7–25.06, 3CH₃–); (43.19, –CH₂–); (56.59, CH–NH–); (68.48, –CH₂–O–); (128.81–145.94, C_arom); (152.66, CO). MS: C₁₄H₁₉NSO₄; MW = 297 g/mol; m/z = 233 (C₁₄H₁₉NO₂⁺, 7%); m/z = 176 (C₁₀H₁₀NO₂⁺, 15%); m/z = 155 (C₇H₇SO₂⁺, 100%); m/z = 91 (C₇H₇⁺, 71%). Anal. calc. for C₁₄H₁₉NO₄S (297.37): C, 56.55; H, 6.44; N, 4.71. Found: C, 55.30; H, 6.32; N, 4.60.

4.25 (4S)-3-(4-Methylbenzenesulfonyl)-4-[(1′S)-1′-methylpropyl]oxazolidin-2-one: 3m

Yield = 95%; m.p.: 170–172 °C [hexane:ethylacetate (90:10)]; [α]_D = +41 (c = 1, CHCl₃). IR (cm⁻¹): ν_CO = 1774. ¹H NMR (300 MHz, CDCl₃): 0.72 (d, 3H); 0.96 (t, 2H); 2.43 (s, 3H); 4.09–4.54 (m, 3H); 7.32–7.96 (AA′BB′, 4H). ¹³C NMR (75 MHz, CDCl₃): (11.54, 11.90, 2CH₃–); (25.51, –CH–) (36.89, –CH₂–); (61.31, CH–NH–); (63.82, –CH₂–O–); (127.32–138.41, C_arom); (152.75, CO). MS: C₁₄H₁₉NSO₄; MW = 297 g/mol; m/z = 233 (C₁₄H₁₉NO₂⁺, 10%); m/z = 240 (C₁₀H₁₀NSO₄⁺, 18%); m/z = 155 (C₇H₇SO₂⁺, 100%); m/z = 91 (C₇H₇⁺, 58%). Anal. calc. for C₁₄H₁₉NO₄S (297.37): C, 56.55; H, 6.44; N, 4.71. Found: C, 56.50; H, 6.42; N, 4.62.

4.26 (4S)-3-(4-Methylbenzenesulfonyl)-4-methyloxazolidin-2-one: 3n

Yield = 97%; m.p.: 117–119 °C [hexane:ethylacetate (90:10)]; [α]_D = +52.2 (c = 0.5, CHCl₃). IR (cm⁻¹): ν_CO = 1779. ¹H NMR (300 MHz, CDCl₃): 1.52 (d, 3H); 2.4 (s, 3H); 3.89–4.57 (m, 3H); 5.15 (d, 1H); 7.33–7.95 (AA′BB′, 4H). ¹³C NMR (75 MHz, CDCl₃): (21–22, 2CH₃–); (53.96, CH–NH–); (69.92, –CH₂–O–); (128.71–150.95, C_arom); (152.50, CO). MS: C₁₁H₁₃NSO₄; MW = 255 g/mol; m/z = 255 (M⁺, 4%); m/z = 254 (C₁₁H₁₂NSO₄⁺, 32%); m/z = 191 (C₁₁H₁₃NO₂⁺, 50%); m/z = 91 (C₇H₇⁺, 73%); m/z = 64 (SO₂⁺, 74%). Anal. calc. for C₁₁H₁₃NO₄S (255.29): C, 51.75; H, 5.13; N, 5.49. Found: C, 51.70; H, 5.20; N, 5.40.

4.27 (4R)-3-(4-Methylbenzenesulfonyl)-4-phenyloxazolidin-2-one: 3o

Yield = 95%; m.p.:149–151 °C [hexane:ethylacetate (90:10)]; [α]_D = −39.5 (c = 0.5, CHCl₃). IR (cm⁻¹): ν_CO = 1774. ¹H NMR (300 MHz, CDCl₃): 2.37 (d, 3H); 4.25–4.29 (m, 1H); 5.41–5.43 (m, 1H); 7.09–7.31 (m, 9H). ¹³C NMR (75 MHz, CDCl₃): (22.01, 1CH₃–); (60.75, CH–NH–); (70.87, –CH₂–O–); (127.41–145.59, C_arom); (152.45, CO). MS: C₁₆H₁₅NSO₄; MW = 317 g/mol; m/z = 253 (C₁₆H₁₅NO₂⁺, 71%); m/z = 91 (C₇H₇⁺, 100%); m/z = 77 (C₆H₅⁺, 55%). Anal. calc. for C₁₆H₁₅NO₄S (317.36): C, 60.55; H, 4.76; N, 4.41. Found: C, 60.52; H, 4.72; N, 4.25.

4.28 (4S)-3-(4-Methylbenzenesulfonyl)-4-benzyloxazolidin-2-one: 3p

Yield = 96%; m.p.: 136–138 °C [hexane:ethylacetate (90:10)]; [α]_D = +36.2 (c = 0.5, CHCl₃). IR (cm⁻¹): ν_CO = 1774. ¹H NMR (300 MHz, CDCl₃): 2.37 (d, 3H); 4.25–4.29 (m, 1H); 5.41–5.43 (m, 1H); 7.09–7.31 (m, 9H). ¹³C NMR (75 MHz, CDCl₃): (22, 1CH₃–); (41.25, –CH₂–); (60.7, CH–NH–); (70.8, –CH₂–O–); (127.40–145.59, C_arom); (152.45, CO). MS: C₁₆H₁₅NO₄S; MW = 317 g/mol; m/z = 253 (C₁₆H₁₅NO₂⁺, 71%); m/z = 155 (C₇H₇SO₂⁺, 10%); m/z = 91 (C₇H₇⁺, 100%); m/z = 77 (C₆H₅⁺, 55%). Anal. calc. for C₁₇H₁₇NO₄S (331.39): C, 61.62; H, 5.17; N, 4.23. Found: C, 61.50; H, 5.20; N, 4.20.

Acknowledgments

We are grateful to the DGRSRT (the Direction générale de la Recherche scientifique et de la Rénovation technologique) for grants to ‘Laboratoire de synthèse organique asymétrique et catalyse homogène’.

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[26] B.M. Berry; D. Craig Synlett (1992), p. 41

[27] J.A. Dale; D.L. Dull; H.S. Mosher J. Org. Chem., 34 (1969), p. 2543

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