通过还原 N-叔丁基亚磺酰基α-氯亚胺不对称合成氮丙啶。
Asymmetric synthesis of aziridines by reduction of N-tert-butanesulfinyl alpha-chloro imines.
作者信息
Denolf Bram, Leemans Erika, De Kimpe Norbert
机构信息
Department of Organic Chemistry, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium.
出版信息
J Org Chem. 2007 Apr 27;72(9):3211-7. doi: 10.1021/jo0624795. Epub 2007 Mar 31.
Reduction of (RS)-N-tert-butanesulfinyl alpha-halo imines afforded chiral aziridines in good to excellent yields. Upon reduction of (RS)-N-tert-butanesulfinyl alpha-halo imines with NaBH4 in THF, in the presence of 10 equiv of MeOH, (RS,S)-beta-halo sulfinamides were formed in excellent yield (up to 98%) with very good stereoselectivity (>98:2). Simple treatment of the latter (RS,S)-beta-halo-tert-butanesulfinamides with KOH afforded the corresponding (RS,S)-N-(tert-butylsulfinyl)aziridines in quantitative yields. On the contrary, its epimer, (RS,R)-N-(tert-butylsulfinyl)aziridine was synthesized by switchover of the reducing agent from NaBH4 to LiBHEt3. (RS,R)-N-(tert-Butylsulfinyl)aziridines were synthesized in good yields (up to 85%) and diastereoselectivity (up to 92:8) by reduction of (RS)-N-tert-butanesulfinyl alpha-halo imines with LiBHEt3 in dry THF and subsequent treatment with KOH. All chiral aziridines were obtained as a single diastereomer after recrystallization (overall yield up to 91%) or after flash chromatography.
还原（RS）-N-叔丁基亚磺酰基α-卤代亚胺可得到产率良好至优异的手性氮丙啶。在四氢呋喃中用硼氢化钠还原（RS）-N-叔丁基亚磺酰基α-卤代亚胺时，在10当量甲醇存在下，（RS，S）-β-卤代亚磺酰胺以优异的产率（高达98%）和非常好的立体选择性（>98:2）形成。用氢氧化钾简单处理后者（RS，S）-β-卤代叔丁基亚磺酰胺，可定量得到相应的（RS，S）-N-（叔丁基亚磺酰基）氮丙啶。相反，通过将还原剂从硼氢化钠切换为三乙基硼氢化锂，合成了其差向异构体（RS，R）-N-（叔丁基亚磺酰基）氮丙啶。在干燥的四氢呋喃中用三乙基硼氢化锂还原（RS）-N-叔丁基亚磺酰基α-卤代亚胺，随后用氢氧化钾处理，以良好的产率（高达85%）和非对映选择性（高达92:8）合成了（RS，R）-N-（叔丁基亚磺酰基）氮丙啶。所有手性氮丙啶在重结晶后（总产率高达91%）或快速柱色谱后均以单一非对映体形式获得。
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