Regio- and stereo-selectivity issues in radical brominations of allylic units of vinylogous esters/carbonates bearing the 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl auxiliary and in nucleophilic displacements of the derived allylic bromides †
作者:A. Paula Esteves、Ana M. Freitas、Clive M. Raynor、Richard J. Stoodley
DOI:10.1039/b000901f
日期:——
Under radical conditions, N-bromosuccinimide effects bromination of the methyl group of the 1-oxyallyl unit of (E)-3-methyl-4-(2′,3′,4′,6′-tetra-O-acetyl-β-D-glucopyranosyloxy)but-3-en-2-one 1a, (E)-2-methyl-1-(2′,3′,4′,6′-tetra-O-acetyl-β-D-glucopyranosyloxy)pent-1-en-3-one 1b and methyl/ethyl (E)-2-methyl-3-(2′,3′,4′,6′-tetra-O-acetyl-β-D-glucopyranosyloxy)prop-2-enoate 1c/1d to give the bromoethyl