Enantioselective Intramolecular Cyclopropanations of Allylic and Homoallylic Diazoacetates and Diazoacetamides Using Chiral Dirhodium(II) Carboxamide Catalysts
作者:Michael P. Doyle、Richard E. Austin、A. Scott Bailey、Michael P. Dwyer、Alexey B. Dyatkin、Alexey V. Kalinin、Michelle M. Y. Kwan、Spiros Liras、Christopher J. Oalmann
DOI:10.1021/ja00126a016
日期:1995.5
counterparts, but allylic diazoacetates are subject to greater variations in enantioselectivities with changes in substitution patterns on the carbon-carbon double bond. For example, the enantioselectivities in the intramolecular cyclopropanations of 3-allcyl/aryl-2(Z)-alken-l-y1 diazoacetates are generally 194%, whereas the cyclizations of the homologous 4-alkyl/aryl-3(Z)-alken1-yl diazoacetates are typically
手性二铑 (I1) 四[2-吡咯烷酮-S(S)-羧酸甲酯]、Rhz(SS-MEPY)4 (7) 及其对映异构体催化烯丙基和高烯丙基重氮乙酸酯 loa-p 和 22a-j 的重氮分解, Rhz(5RMEPY)4 (S),产生相应的分子内环丙烷化产物 lla-p 和 23a-j,产率良好至极好,并具有出色的对映选择性。使用烯丙基重氮乙酸盐观察到比使用它们的同型烯丙基对应物更高的对映控制,但是随着碳-碳双键上的取代模式的变化,烯丙基重氮乙酸盐的对映选择性变化更大。例如,3-烷基/芳基-2(Z)-链烯-1-y1重氮乙酸酯的分子内环丙烷化反应的对映选择性通常为194%,而同源的 4-烷基/芳基-3(Z)-烯1-基重氮乙酸酯的环化通常在 70-90% ee 的范围内。相应的 3-alkyYaryl-2(E)-alken-1-y1 和 4-烷基/芳基-3(E)-alken-1-yl 重氮乙酸酯发生环化,ee