An unprecedented aryne-mediated dearomatization reaction is described. An aryne intermediate generated from arenesulfonyl ynamide-tethered triynes and tetraynes reacts with both the pi-systems of a tethered alkene and the arenesulfonyl group to generate cyclohexa-1,3-diene-containing pentacyclic and hexacyclic frameworks. Density functional theory (DFT) calculations show a nucleophilic dearomatization mechanism involving a zwitterionic intermediate derived from an aryne. A novel halogen effect on the efficiency of the dearomatization and deterrence of aromatization of the cyclohexa-1,3-diene moiety was also observed.
Highly Streoselective synthesis of bicyclo[2.1.1]hexenes-5- ny transmetallation of a tetra-alkyl tin.
作者:Richard H. Newman-Evans、Barry K. Carpenter
DOI:10.1016/s0040-4039(00)98417-x
日期:1985.1
Synthesis of the title compounds is achieved by a transmetallation reaction that appears to involve regio- and stereochemical control by chelation with a neighboring hydroxyl function.