Catalyzed Diels−Alder Reaction of Alkylidene- or Arylideneacetoacetates and Danishefsky's Dienes with Lanthanide Salts Aimed at Selective Synthesis of <i>cis</i>-4,5-Dimethyl-2-cyclohexenone Derivatives
of 1a. The thermal version of the same cycloaddition results in a decrease in the cis arrangement of the 5-methyl and the 4-alkoxycarbonyl groups on 2-cyclohexenone. The catalyzed reaction of (E)-1a unexpectedly affords the cis-arranged 3a. The reaction path for the catalyzed Diels-Alder reaction is postulated on the basis of these results.
1,2-Acyl Transfer Reaction for the Construction of Multiple Carbonyl-Functionalized Architecture by Sm(II)-Induced Tandem Formation and Breaking of Cyclopropanol
作者:Tsutomu Inokuchi
DOI:10.1021/jo0402529
日期:2005.2.1
An efficient 1,2-acyl groupmigration reaction based on contiguous formation and breaking tactics of 1-oxycyclopropane-2-carboxylate as an intermediate is developed. Thus, the reduction of 2-cyclohexenones, bearing gem-acyl/alkoxycarbonylgroups at the C4 position, with Sm(II) reagent leads to 2-acyl-4-oxycyclohexanecarboxylates via cyclization followed by retro-aldol cleavage of the resulting donor/acceptor