The order of addition of salt-free ethyllithium/benzene solution to enantiomerically pure acylketene acetal 1 dictates the product formed in a chemospecific manner. Introduction of lithium bromide removes the distinction.
Enantiomerically pure ketals in synthesis. Diastereoselective formation of β-keto and β-hydroxy ketals
作者:Clark N. Eid、Joseph P. Konopelski
DOI:10.1016/s0040-4039(00)79468-8
日期:1991.1
Enantiomerically pure acylketene acetals were employed to generate a homochiral β-keto ketal through a highly diastereoselective lithium enolate quench. The β-keto ketal, which was also prepared through a desymmetrization ketalization reaction on a meso dione, was employed in the synthesis of the isomers of the insect pheromone sitophilure.