Phase-Transfer-Catalyzed Asymmetric Alkylation of α-Benzoyloxy-β-keto Esters: Stereoselective Construction of Congested 2,3-Dihydroxycarboxylic Acid Esters
作者:Takuya Hashimoto、Keigo Sasaki、Kazuhiro Fukumoto、Yuichi Murase、Naoyuki Abe、Takashi Ooi、Keiji Maruoka
DOI:10.1002/asia.200900344
日期:2010.3.1
Highly enantioselective phase‐transfer‐catalyzed alkylation of tert‐butyl 2‐benzoyloxy‐3‐oxobutanoate was realized by the use of an N‐spiro chiral quaternary ammonium salt, as a complementary approach to the asymmetric hydroxylation of α‐alkyl‐β‐keto esters. The synthetic utility of the alkylated compounds is highlighted by the diastereoselective reduction and alkylation of the remaining ketone moiety
通过使用N-螺环手性季铵盐,实现了对映体2-苯甲酰氧基-3-氧代丁酸叔丁酯的高度对映选择性相转移催化烷基化,作为α-烷基-β-酮不对称羟基化的一种补充方法酯。烷基化化合物的合成效用通过剩余的酮部分的非对映选择性还原和烷基化而突出,从而得到各种对映异构体富集的拥挤的2,3-二羟基羧酸酯。