RHODIUM(II)-CATALYZED DECOMPOSITION OF BETA,PSI-UNSATURATED DIAZO-COMPOUNDS

The Rh(II)-catalyzed decomposition of beta,gamma-unsaturated diazo ket ones 1 in the presence of MeOH leads via vinylogous Wolff rearrangemen t to gamma,delta-unsaturated esters 6 (Schemes 1 and 2) A modest asymm etric induction is achieved when the reaction is carried out with chir al tetrakis(pyrrolidinecarboxylato)- or tetrakis(oxazolidinonato)dirho dium(II) complexes. Vinyl and phenyl diazoacetates 11 and 20, respecti vely, or 1-diazo-3-phenyl-propan-2-one (25), when subjected to the sam e reaction conditions, react by OH insertion with MeOH 3-5). In the ab sence of MeOH, phenyl diazoacetates 20 and 25 undergo intramolecular C H insertion to 22 and 26, respectively. Intramolecular CH insertion oc curs with N-aryldiazoamides 23 even in the presence of MeOH (Scheme 5) .