Transition Metal-Diene Complexes in Organic Synthesis, Part 18.1Iron-Mediated [2+2+1] Cycloadditions of Diynes and Carbon Monoxide: Selective Demetalation Reactions

Abstract

The iron-mediated [2+2+1] cycloaddition of the silylated terminal diynes 1 affords a broad range of tricarbonyliron-complexed carbo- and heterobicyclic cyclopentadienones 2. Demetalation of the iron complexes 2 can be controlled to afford either the free cyclopentadienones 5 or the isomerized and protodesilylated dienones 6.