Catalytic asymmetric oxidation of tert-butyl disulfide.: Synthesis of tert-butanesulfinamides, tert-butyl sulfoxides, and tert-butanesulfinimines
Catalytic asymmetric oxidation of tert-butyl disulfide.: Synthesis of tert-butanesulfinamides, tert-butyl sulfoxides, and tert-butanesulfinimines
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DOI：
10.1021/ja9809206
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发表时间：
1998-08-19
影响因子：
15
通讯作者：
Ellman, JA
中科院分区：
文献类型：
--
作者：
Cogan, DA;Liu, GC;Ellman, JA
描述了叔丁基二硫醚（1）催化不对称氧化的第一个实例。产物叔丁基硫代亚磺酸叔丁酯（2）以大于或等于92%的产率以91%的对映体过量在1摩尔的规模上获得。在0.25mol% VO（acac）（2）和0.26mol%手性Schiff碱配体6a存在下，H2 O2作为化学计量的氧化剂的应用既方便又具有成本效益。硫代亚磺酸酯2是化学和光学稳定的，并且通过叔丁基硫醇盐的立体特异性亲核置换作为手性叔丁基亚磺酰基化合物的优良前体。在液氨和THF中加入LiNH 2得到叔丁基亚磺酰胺（3; 91%产率）。单次重结晶从二硫化物1以71-75%的总产率提供对映体纯的3。对映体纯的硫代亚磺酸酯2也容易地和立体特异性地与格氏试剂、有机锂、氨基锂和亚胺锂盐反应，以良好的产率提供对映体纯的手性亚砜、亚磺酰胺和亚磺亚胺。
The first example of the catalytic asymmetric oxidation of tert-butyl disulfide (1) is described. The product, rert-butyl tert-butanethiosulfinate (2) is obtained with 91% enantiomeric excess in yields of greater than or equal to 92% on scales as large as 1 mel. The application of H2O2 as stoichiometric oxidant in the presence of 0.25 mol % of VO(acac)(2) and 0.26 mol % of a chiral Schiff base ligand, 6a, is both convenient and cost-effective. Thiosulfinate ester 2 is chemically and optically stable and serves as an excellent precursor to chiral tert-butanesulfinyl compounds by the stereospecific nucleophilic displacement of tert-butyl thiolate. Addition of LiNH2 in liquid ammonia and THF provides tert-butanesulfinamide (3; 91% yield). A single recrystallization provides enantiomerically pure 3 in 71-75% overall yield from disulfide 1. Enantiomerically pure thiosulfinate ester 2 also reacts readily and stereospecifically with Grignard reagents, organolithiums, lithium amides, and lithium imine salts to provide enantiomerically pure chiral sulfoxides, sulfinamides, and sulfinimines in good yield.