Steric promotion in the cycloplatination of primary amines

摘要

The reactions of primary amines (S)-(-)-alpha-methylbenzylamine (1a) and (R)-(+)-1-(1-naphthyl)ethylamine (1b) with cis-[PtCl2(dmso)(2)] in the presence of Na(CH3CO2) carried out in refluxing toluene-methanol mixtures produced cyclometallated compounds [PtCl{NH2CH(CH3)C6H4}[SOMe2)] (2a) and [PtCl{NH2CH(CH3)C10H6}{SOMe2}] (2b) in moderate and quantitative yields, respectively. Compound 2b was also obtained at room temperature, in the absence of Na(CH3CO2). The reactions of 2a and 2b with phosphines were studied. The obtained compounds were fully characterized and the factors that facilitate cycloplatination of primary amines are discussed.