Functional Group Hybrids. Reactivity of α'-Nucleofuge α,β-Unsaturated Ketones. 2. Reactions with Malonate Anion. Concerning the Mechanism of the Favorskii Rearrangement

Article abstract of DOI:10.1021/jo00024a015

The scope and limitations of the reaction of α'-nucleofuge α,β-unsaturated ketones with sodium dimethyl malonate has been studied systematically.The substrates with good nucleofuges (halides, mesylate) give cyclopropanols upon reaction with malonate anion by way of a conjugate Favorskii reaction.In reactions with substrates containing the poorer nucleofuge (acetoxy) conjugate addition proceeded without entering the Favorskii manifold.Concerning the mechanism of the Favorskii reaction, it is suggested that the loss of the nucleofuge occurs to give a 2-oxyallyl cation, but that disrotatory ring closure is facile and the only products observed result from nucleophilic trapping of cyclopropanones to yield cyclopropanols in fair to good yield.