Radical Cyclization of (Bromomethyl)dimethylsilyl Propargyl Ethers. Regio-, Chemo-, and Stereoselectivity

Article abstract of DOI:10.1021/jo00037a026

Radical cyclization of (bromomethyl)dimethylsilyl propargyl ether derivatives 1 is a powerful reaction with a high degree of regio-, chemo-, and stereoselectivity.Trisubstituted olefins 3, cyclopentene derivatives 5, and diquinane system 7j are obtained in good yields by a judicious choice of unsaturated substituents.Triquinane frameworks could be obtained stereoselectively from a suitable acyclic substrate of type 1 in a one-pot reaction.First attempts have not yet allowed us to aim at this goal due to interesting (1,5) hydrogen transfers.Moreover, we have intercepted, for the first time, the α-cyclopropyl radical which is involved in the Storck-Beckwith mechanism of the 5-versus 6-membered ring formation in the vinyl radical cyclization.