Oxidative addition, carbonyl insertion, and o-demethylation reactions of rhodium complexes with tertiary 2-methoxyphenylphosphines

Abstract

The complex trans-[RhCl(CO){PMe₂(2-MeOC₆H₄)}₂] undergoes rapid oxidative addition with HCl, MeCl, MeI, CCl₄, Cl₂, and PhCOCl (R–X) to give rhodium(III) adducts of the normal type, i.e.[RhClXR(CO)L₂]. Addition of HCl is readily reversed. Allyl chloride (R–X) also adds reversibly in benzene solution but in polar solvents the adduct rapidly isomerizes to the acyl complex [RhCl₂(COCH₂CH:CH₂)L₂]. Analogous acyl complexes were prepared from CH₂:C(Me)CH₂Cl, MeCH:CHCH₂Cl, and MeCHClCH:CH₂. The complex trans-[RhCl(CO){PBu₂^t(2-MeOC₆H₄)}₂] resists oxidative addition reactions but in boiling propan-2-ol demethyfation of one ligand occurs to give the chelate [R[graphic omitted]){PBu₂^t(2-MeOC₆H₄)}]. RhCl₃,3H₂O reacts with PMe₂(2-MeOC₆H₄) to give ultimately [R[graphic omitted])₃] and with PBu₂^t(2-MeOC₆H₄) to give the intensely blue rhodium(II) species [R[graphic omitted])₂], accompanied by small amounts of what appear to be carbonyl or hydrido-species.