59 The Ironcarbonyl-Dibromo Ketone Reaction : Intramolecular 3+4 and 3+2 Cyclocoupling Reactions and their Application to the Terpenoid Synthesis

Abstract

The intramolecular version of ironcarbonyl promoted reaction of polybromo ketones and olefin or diene substrates has been applied to the synthesis of certain terpenoids. The reductive cyclization of 1 and 2 affords the oxoguaian skeleton 12 and 13, respectively, in a stereospecific manner. (±)-Camphor and (±)-campherenone has been synthesized from the dibromo ketone 15 and 16, respectively, realizing a chemical analogue of biosynthesis.