Asymmetric synthesis of a chiral diarsine ligand via a cycloaddition reaction between 3,4-dimethyl-1-phenylarsole and diphenylvinylarsine.

The organopalladium complex containing ortho-metallated (S)-[1-(dimethylamino)ethyl]naphthalene as a chiral auxiliary has been successfully employed to promote the asymmetric cycloaddition reaction between 3,4-dimethyl-1-phenylarsole and diphenylvinylarsine. In the intramolecular cycloaddition reaction, a pair of separable diastereomeric palladium complexes was obtained in the ratio of 6:1. The chiral naphthylamine auxiliary could be removed chemoselectively from the template by treatment with HCl and subsequently NaI to generate the neutral diiodo complex [(As-As)PdI2]. Treatment of the diiodo complex with KCN gave the enantiomerically pure As-As bidentate ligand in quantitative yield. In contrast to the reported similar P-P and As-P analogues, both arsenic donors in the diiodo complex could be readily eliminated to produce a structurally novel dimetallic complex. [ABSTRACT FROM AUTHOR]