Construction of contiguous tetrasubstituted chiral carbon stereocenters via direct catalytic asymmetric aldol and mannich-type reactions
作者:Shigeki Matsunaga、Tatsuhiko Yoshino
DOI:10.1002/tcr.201100020
日期:2011.9.29
Catalytic asymmetric synthesis of unnatural amino acids with vicinal tetrasubstituted chiral carbon stereocenters is described. In the first part, direct catalytic asymmetric aldol reaction of simple non‐activated ketone electrophiles with α‐substituted α‐isothiocyanato ester donors was realized. A Mg/Schiff base catalyst promoted the aldol reaction, and α‐amino‐β‐hydroxy esters were obtained in up
描述了具有邻位四取代的手性碳立体中心的非天然氨基酸的催化不对称合成。在第一部分中,实现了简单的未活化的酮亲电体与α-取代的α-异硫氰酸酯供体的直接催化不对称醛醇缩合反应。镁/席夫碱催化剂促进了醛醇缩合反应,在高达98%ee和98:2 dr的条件下获得了α-氨基-β-羟基酯。第二部分,镁/席夫碱催化剂和Sr /席夫碱催化剂用于酮亚胺的立体发散性直接不对称曼尼希型反应。Mg / Schiff碱催化剂产生合成α-β-二氨基酯,而Sr / Schiff碱催化剂产生抗α-β-二氨基酯,对映选择性高至高,对比例高达97%ee。DOI 10.1002 / tcr.201100020