Asymmetric Vinylogous Mukaiyama-Mannich Reactions of Heterocyclic Siloxy Dienes with Ellman's Fluorinated Aldimines

摘要

Vinylogous Mukaiyama Mannich reactions of furan and pyrrole based dienoxy silanes with alpha-fluoroalkyl sulfinyl imines provide a powerful synthetic access to a variety of amino fluoroalkyl gamma-butenolide-type and butyrolactam frameworks with high regio- and diastereoselectivity. Anti-configured adducts were obtained in all cases, independent of the nature of the heteroatom (O or N) present in the dienoxy silane. The absolute configuration of the adducts prepared was unequivocally established by X-ray crystallographic analysis. It is noteworthy that the introduction of substituents at the gamma-position of the heterocyclic partner allows the generation of adducts bearing chiral quaternary centers.