Regio- and Diastereoselective Conjugate Addition to 4,4-Dimethylcyclohexadienones
作者:Donatella Giomi、Michela Piacenti、Alberto Brandi
DOI:10.1002/ejoc.200500426
日期:2005.11
Conjugate addition of vinyl cuprate and dimethyl malonate to 4,4-dimethylcyclohexa-2,5-dienones has allowed facile access to mono- and bis-adducts in satisfactory yields. While the high diastereoselectivity of such processes to afford trans-bis-adducts was predictable, an unprecedented regioselectivity was observed with 2,4,4-trimethylcyclohexa-2,5-dienone, with the first addition occurring exclusively
乙烯基铜酸盐和丙二酸二甲酯与 4,4-二甲基环六-2,5-二烯酮的共轭加成使得以令人满意的产率轻松获得单加合物和双加合物。虽然此类过程提供反式双加合物的高非对映选择性是可以预测的,但观察到 2,4,4-三甲基环六-2,5-二烯酮具有前所未有的区域选择性,第一次加成仅发生在 C-5 碳原子上(远离甲基)并且第二次添加庞大的亲核试剂如丙二酸二甲酯甚至可以防止。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)