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 furnishes a highly functionalized bridged bicyclo [4.2.1]nonenecarboxylic acid derivative in 88 % yield.
Alkylation of (η<sup>6</sup>-Arene)Mn(CO)<sub>3</sub> Cations with Organozinc Reagents
作者:Ming-Chang P. Yeh、Chong-Cheng Hwu、An-Tang Lee、Ming-Shan Tsai
DOI:10.1021/om010338h
日期:2001.11.1
Additions of allylic and benzylic zinc reagents to (eta (6)-arene)Mn(CO)(3) cations proceed in an anti fashion to give the C-6 allylic- and benzylic-substituted (eta (5)-cyclohexadienyl)Mn(CO)(3) neutral complexes, respectively. The reaction of less reactive primary organozinc reagents bearing an ester or a cyano group with the cations affords the a-alkylation products. Treatment of the organozinc reagent containing an acetoxy group with (eta (6)-benzene)Mn(CO)(3)(+) complex in THF results in alkylation of the cation at the C-2 position of THF.