Hexamethyldisilazanes mediated one-pot intramolecular Michael addition–olefination reactions leading to exo-olefinated bicyclo[6.4.0]dodecanes
作者:Hiroshi Fujishima、Hiroshi Takeshita、Shuichi Suzuki、Masahiro Toyota、Masataka Ihara
DOI:10.1039/a904484a
日期:——
A novel one-pot reaction for the synthesis of exo-olefinated bicyclo[6.4.0]dodecanes 23 has been developed on the basis of an intramolecular Michael reaction of phenylsulfonyl compounds 4 with potassium hexamethyldisilazide (KHMDS) and a sequential reaction with an excess of methoxymethyl chloride (MOMCl). By this reaction, an exo-olefin group was regioselectively introduced at the α-position to the carbonyl group in the 6-membered ring in high yield. The regioselective introduction of the olefin moiety could be envisaged to proceed through a Mannich-type reaction involving the aminomethylating agent 24, which, in turn, is generated in situ by the action of HMDS on MOMCl.
开发了一种新颖的一锅法反应,用于合成外烯基双环[6.4.0]十二烷 23,该反应基于苯基磺酰化合物 4 与六甲基二硅氮化钾(KHMDS)进行的分子内迈克尔反应,以及与过量的甲氧基甲基氯(MOMCl)进行的序贯反应。通过该反应,外烯基团以区域选择性的方式引入到6元环中的羰基α位,并获得了高产率。烯烃官能团的区域选择性引入可以设想是通过一种曼尼希反应进行的,该反应涉及氨基甲基化试剂24,该试剂又是在HMDS与MOMCl作用下就地生成的。