Highly Enantioselective Phase-Transfer Catalytic α-Alkylation of α-<i>tert</i>-Butoxycarbonyllactams: Construction of β-Quaternary Chiral Pyrrolidine and Piperidine Systems
作者:Yohan Park、Young Ju Lee、Suckchang Hong、Mi-hyun Kim、Myungmo Lee、Taek-Soo Kim、Jae Kyun Lee、Sang-sup Jew、Hyeung-geun Park
DOI:10.1002/adsc.201100542
日期:2011.12
A new enantioselective α-alkylation of α-tert-butoxycarbonyllactams for the construction of β-quaternary chiral pyrrolidine and piperidine core systems is reported. α-Alkylations of N-methyl-α-tert-butoxycarbonylbutyrolactam and N-diphenylmethyl-α-tert-butoxycarbonylvalerolactam under phase-transfer catalytic conditions (solid potassium hydroxide, toluene, −40 °C) in the presence of (S,S)-3,4,5-trifluorophenyl-3
报道了用于构建β-季手性吡咯烷和哌啶核心体系的α-叔丁氧基羰基内酰胺的新对映选择性α-烷基化。α-烷基化的ñ -甲基- α-叔-butoxycarbonylbutyrolactam和ñ -二苯基甲基-α-叔-butoxycarbonylvalerolactam相转移催化条件下(固体氢氧化钾,甲苯,-40℃)在存在下(小号,小号) -3,4,5-三氟苯基-3,3',5,5'-四氢-2,6-双(3,4,5-三氟苯基)-4,4'-spirobi [4 H -dinaphth [2, 1- c:1',2'- e ]氮杂pin]溴化物[(S,S)-NAS Br](5mol%)以非常高的化学(高达99%)和光学收率(高达98%ee)提供了相应的α-烷基-α-叔-丁氧基羰基内酰胺。我们的新催化体系为基于吡咯烷和哌啶的生物碱以及具有β-季碳中心的手性中间体提供了有吸引力的合成方法。