A Direct and Selective Syntheses of α,α-Dichloro- and α-Chloro-ethyl Ketones by the Reaction of Alkyl Carboxylates with 1,1-Dichloroethyllithium
作者:Isamu Shiina、Yumiko Imai、Akifumi Kagayama、Teruaki Mukaiyama
DOI:10.1246/cl.2000.190
日期:2000.2
generated by treating 1,1-dichloroethane (4) with lithium diisopropylamide (LDA) or n-butyllithium, reacted with alkyl carboxylates to afford the corresponding α,α-dichloro- or α-monochloro-ethyl ketones selectively in good to high yields. According to the above alkylation method, synthetic intermediates of Taxol, optically active α,α-dichloroethyl polyoxyketone 2 and α-chloroethyl polyoxyketone 3
1,1-二氯乙基锂 (5),通过用二异丙基氨基锂 (LDA) 或正丁基锂处理 1,1-二氯乙烷 (4) 生成,与羧酸烷基酯反应得到相应的 α,α-二氯-或 α-单氯-选择性地以良好到高产率制备乙基酮。按照上述烷基化方法,以旋光聚氧羧酸甲酯1为原料,分别合成了紫杉醇的合成中间体旋光α,α-二氯乙基聚氧酮2和α-氯乙基聚氧酮3,收率良好。