Synthesis of Carbohydrate Derived α-Methylene-γ-lactones by Diasterecseldctive, Low Temperature Reformatsky-Type Reactions

Abstract
Hexopyranoside- and hexofuranose uloses with either ethyl 2-(branamethyl)acrylate in the presence of laminar Zn/Ag-graphite or ethyl 2-(trimethylsilylinethyl)acrylate/tetra-n-butylanrnonium fluoride undergo stereoselective branching, mainly with formation of spiro α-methylene-γ-lactones.