Crystal structures of deoxygenation products and the characteristics of reactions of phenyl-(trihalomethyl)mercury with tetraphenylcyclone

Abstract

The single crystal structures of thegem-dihalides (3a and 3b) produced from the reactions of tetraphenylcyclone (TPCP) with phenyl(trihalomethyl)mercury (trihalo = tribromo, bromodichloro) are reported. The structural parameters of the X-ray single crystal analysis vary slightly with the radius of the halogen atom in dihalides and are found to be related to the yields of the deoxygenation products. These results support the proposed mechanism for the carbene reaction of this type and reflect the key role of the structural characteristics of the incipient carbonyl ylide intermediate in choosing different competitive reaction pathways.