Synthesis of the cyclopentadienone rhodium complexes and investigation of their catalytic activity in the reductive amination of aldehydes in the presence of carbon monoxide

Abstract

Reaction of bis(p-tolyl-propargyl)-tosylamide with [(cod)RhCl]2 in the presence of CO gives the cyclopentadienone complex [(Cpd’)Rh(CO)Cl]n (Cpd’ = TsN(CH2)2C4(Tol)2CO). Its dissolution in DMSO or pyridine leads to decarbonylation and formation of the adducts (Cpd’)Rh(DMSO)2Cl and (Cpd’)Rh(Py)2Cl. The reaction of [(Cpd’)Rh(CO)Cl]n with AgPF6 and p-xylene produces the sandwich arene complex [(Cpd’)Rh(p-xylene)]PF6, in which the arene can be substituted by tBuNC ligand to give [(Cpd’)Rh(tBuNC)3]PF6. The arene complex acts as an efficient catalyst for the reductive amination of carbonyl compounds in the presence of CO as deoxygenation agent, producing various amines in 75–85% yields.