2-Thiazolyl α-Amino Ketones: A New Class of Reactive Intermediates for the Stereocontrolled Synthesis of Unusual Amino Acids
作者:Alessandro Dondoni、Daniela Perrone
DOI:10.1055/s-1993-26021
日期:——
The thiazole-based one carbon homologation of four α-amino acids (L-phenylalanine, L-leucine, L-threonine, and L-serine) to the corresponding α-hydroxy β-amino aldehydes and acids in both configurations at Cα, is described. The methodology involves the following key operations: (i) the conversion of an α-amino ester to a 2-thiazolyl α-amino ketone; (ii) the stereocontrolled reduction of a ketone carbonyl to either syn or anti α,β-amino alcohols; (iii) the aldehyde release from the thiazole ring; (iv) the oxidation of the aldehyde to a carboxylic acid. The methodology was only partially applied to L-phenylglycine because of some limitations in operation (i).
描述了四种α-氨基酸(L-苯丙氨酸、L-亮氨酸、L-苏氨酸和L-丝氨酸)的噻唑基单碳同源化,生成相应的α-羟基β-氨基醛和酸,且在Cα上具有两种构型。该方法论涉及以下关键操作:(i)将α-氨基酯转化为2-噻唑基α-氨基酮;(ii)对酮羰基进行立体选择性还原,生成syn或anti的α,β-氨基醇;(iii)从噻唑环中释放醛;(iv)将醛氧化为羧酸。由于操作(i)的一些限制,该方法论仅部分应用于L-苯甘氨酸。