Generation of allenic samarium complexes from propargylic ethers and (C 5Me 5) 2Sm(thf) 2, and their electrophilic trapping

Abstract

Allenic samarium complexes are readily generated in high yields by the reaction of propargylic benzyl ethers with (C 5Me 5) 2Sm(thf) 2. Electrophilic trapping of the complexes derived from the secondary and tertiary ethers with cyclohexanone and dimethylphenylsilyl chloride gives the corresponding propargylic products selectively, whereas α-allenic alcohols are predominantly obtained in the reaction of the complexes, generated from the primary ethers, with cyclohexanone.