A new asymmetric synthetic method to prepare α,α-dialkylmalonates for the construction of a quaternary carbon center via phase-transfer catalytic (PTC) alkylation has been developed. Enantioselective α-alkylation of 2-methylbenzyl tert-butyl α-methylmalonates under phase-transfer catalytic conditions in the presence of (S,S)-3,4,5-trifluorophenyl-NAS bromide (10) afforded the corresponding α,α-dialkylmalonates
开发了一种新的不对称合成方法,该方法可通过相转移催化(
PTC)烷基化反应制备用于构筑季碳中心的α,α-二烷基
丙二酸酯。在(S,S)-3,4,5-三
氟苯基-NAS
溴化物(10)存在下,在相转移催化条件下2-甲基苄基α-
甲基丙二酸叔丁基叔丁酯的对映选择性α-烷基化,得到相应的α,α-二烷基
丙二酸酯,
化学含量高(高达99%)和光学收率(ee高达91%),可在碱性碱性条件下选择性
水解为
丙二酸单酸,转化为通用的手性中间体。