title: Reagent-directed allylic quadraselection. Chemoselective anti- and syn-Lawton S(N)2' methylation of seven-membered epoxyvinylsulfones.
abstract: Methods have been developed for regio- and stereoselective 1,4-syn or 1,4-anti methylation of seven-membered epoxyvinylsulfones. 1,4-Syn addition is achieved via the combination of Me(2)Zn and catalytic Li(2)CuCl(4), a hitherto unexplored reagent combination. The complementary 1,4-anti addition relies on Cu(I) catalyzed methyl Grignard addition or (CH(3))(3)Al assisted CH(3)Cu addition. The methods described were assayed on four diastereomeric stereodiads and on their parent epoxide.
authors.affiliation: Purdue University, Department of Chemistry, West Lafayette, Indiana 47907, USA.
authors.forename: Wan Pyo
authors.initials: WP
authors.lastname: Hong
authors.forename: Ahmad
authors.initials: A
authors.lastname: El-Awa
authors.forename: Philip L
authors.initials: PL
authors.lastname: Fuchs