Reagent-directed allylic quadraselection. Chemoselective anti- and syn-Lawton S(N)2' methylation of seven-membered epoxyvinylsulfones.
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.
Hong
Wan Pyo
WP
Purdue University, Department of Chemistry, West Lafayette, Indiana 47907, USA.
El-Awa
Ahmad
A
Fuchs
Philip L
PL