o-DPPB-directed stereoselective conjugate addition of organocuprates

Substrate-directed diastereoselective conjugate addition of Gilman cuprates to acyclic enoates has been achieved with the aid of the substrate-bound r eagent-directing o-DPPB-group (o-DPPB=ortho-diphenylphosphanyl benzoate). C ombining o-DPPB-directed hydroformylation with the o-DPPB-directed cuprate addition provides access to building blocks with up to four stereogenic cen ters, which may be of relevance for polyketide synthesis. Limit and scope o f the o-DPPB-directed cuprate addition of Gilman cuprates with respect to e noate structure as well as control experiments which probe the role of the o-DPPB group are reported. (C) 2000 Elsevier Science Ltd. All rights reserv ed.