High Stereocontrol in Aldol Reaction with Ketones: Enantioselective Synthesis of β-Hydroxy γ-Ketoesters by Ester Enolate Aldol Reactions with 2-Acyl-2-alkyl-1,3-dithiane 1-Oxides
作者:José L. García Ruano、David Barros、M. Carmen Maestro、Alexandra M. Z. Slawin、Philip C. Bulman Page
DOI:10.1021/jo000494i
日期:2000.9.1
2-acyl dithiane oxides, with lithium enolates derived from several esters and lactones, proceeds with a high degree of stereocontrol at both carbonyl and enolate prochiral centers, the stereocontrol mainly determined by the configuration of the sulfoxide sulfur atom. The sense of induced stereochemistry observed for ester enolates is different from that seen for lactone enolates. Hydrolysis of the dithiane
掩蔽为非外消旋的2-酰基二噻吩氧化物的1,2-二酮与衍生自数种酯和内酯的烯醇锂的不对称醛醇缩合反应在羰基和烯醇前手性中心均具有高度立体控制,该立体控制主要取决于亚砜硫原子的构型。酯烯醇盐观察到的诱导立体化学的感觉与内酯烯醇盐观察到的不同。主要的非对映异构纯的醛醇缩合产物的二噻吩氧化单元的水解得到对映体纯的叔α-取代的β-羟基-γ-酮酸酯。