Conjugate addition of organocopper reagents to γ-alkoxybutenolides and application to the synthesis of non-racemic alkyl cyclopentenones
作者:Jeremy Robertson、Morgan Ménard、Rhonan Ford、Stephen Bell
DOI:10.1039/b408255a
日期:——
Simple organocopper reagents are shown to undergo anti-stereoselective 1,4-addition to menthyloxy-substituted lactone 1 in the presence of BF3.OEt2; the Lewis acid causes partial epimerisation of the acetal centre after conjugate addition. Enolate alkylation of the adducts leads to di- and trisubstituted lactones that are converted, in favourable cases, into di- and trisubstituted cyclopentenones.
已显示简单的有机铜试剂在BF3.OEt2存在下,经薄荷醇氧基取代的内酯1进行抗立体选择性的1,4-加成;加入共轭物后,路易斯酸引起缩醛中心的部分差向异构化。加合物的乙醇酸酯烷基化导致二和三取代的内酯,在有利的情况下,它们被转化为二和三取代的环戊烯酮。