Michael Addition Reactions of the Highly Functionalized Zinc-Copper Reagents RCu(CN)ZnI to (Tropone)iron Tricarbonyl Promoted by Boron Trifluoride Etherate

The zinc-copper reagents RCu(CN)ZnI, containing various functional groups such as a cyanide, ester, thio ester or benzyl, react with (tropone)iron tricarbonyl in the presence of an excess of boron trifluoride etherate to afford the Michael adducts in excellent yields. Cyano-substituted 1.4-adducts undergo an intramolecular cyclization reaction in situ, leading to highly functionalized bicyclo[5.3.0]decane and-[5.4.0]undecane derivatives, whereas treatments of an ester-substituted 1.4-adduct with lithium diisopropylamide (LDA) under an atmosphere of carbon monoxide furnishs a highly functionalized bridged bicyclo[4.2.1] nonenecarboxylic acid derivative in 88 % yield.