Metal salt-catalysed carbenoids. Part IX. The catalysts in trialkyl phosphite–copper(I) complex catalysed decomposition of diazomalonic esters in cycloalkenes

Abstract

Partial rate data, asymmetric induction studies, interrupted experiments, and additives studies indicate that copper(]) salt-phosphite complexes are destroyed during the course of reactions with dimethyl diazomalonate (1 ) and ethyl diazoacetate (2). All evidence is consistent with the copper(i) being oxidized to copper(ii) and copper(0) being oxidized by impurities in the olefin which most probably are hydroperoxides.Several new copper(1) salt-phosphite complexes have been prepared and examined but none proved as effective for decomposing compound (I) as bis(acetylacetonato)copper(ii).The utility of the chloro(trimethy1 phosphite)copper(i) for decomposing compound (I) is a function of the means of preparation. The three general methods employed furnished samples having superposable i.r. spectra and superposable proton n.m.r. spectra but exhibited varying degrees of line broadening in the srP n.m.r.The chiral mixed phosphite ligand bornane-2.3-diyl phenyl phosphite (3) derived from bornane-2.3-diol failed to induce any asymmetric induction in the reaction between (2) and styrene when complexed with copper(1) iodide even though the ligand is chiral at four carbons and phosphorus.