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.
