More efficient iterative uses of tricarbonyliron complexes are possible by diastereoselective formation of η5-cyclohexadienyl complexes

Abstract Diastereoselective addition of nucleophiles to 1-(RCO)-substituted tricarbony η 4 -cyclohexadiene)iron(0) complexes, and a diastereoselective acid-induced rearrangement to form 1-(branched alkyl)-substituted tricarbonyl( η 5 -cyclohexadienyl)iron(1+) salts, are described. Stereocontrol in the rearrangement has been studied, and HPF 6 , Ac 2 O has been shown to be the most suitable acid to promote diastereoselectivity. The product was reacted with LiCH(SO 2 Ph) 2 , completing one turn of an iterative cycle which formed a chiral centre at each step.