title: An Asymmetric Route to Novel Chiral Cyclohexenones with Spiro-Connected Cyclopentenes. Further Utility of Chiral Bicyclic Thiolactams and the [3,3] Thio-Claisen Products.
abstract: Sequential allylation of chiral, nonracemic thiolactam 8 affords clean thio-Claisen [3,3] products 11. The stereoselectivity of the rearrangement was found to be on the order of 10-11:1, with the exo-endo products responsible for the mixture. Addition of hydride or methyllithium-cerium chloride gave clean addition to the thiolactam in the form of its iminium salts 12. Hydrolysis gave 4,4-dialkylcyclohexenones 15, which were cyclized to the cyclopentene derivatives 16 using Grubbs' catalyst.
authors.affiliation: Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523.
authors.forename: René M.
authors.initials: RM
authors.lastname: Lemieux
authors.forename: Paul N.
authors.initials: PN
authors.lastname: Devine
authors.forename: Mark F.
authors.initials: MF
authors.lastname: Mechelke
authors.forename: A. I.
authors.initials: AI
authors.lastname: Meyers