Asymmetric codimerization of cyclohexa-1,3-diene with ethylene catalysed by chiral aminophosphine-nickel complexes
Abstract
The asymmetric codimerization of cyclohexa-1,3-diene with ethylene is catalysed by the Ni(cyclo-octa-1,5-diene)2–AlEt2Cl–L system where L are chiral aminophosphines; optimization of this catalytic system (–70°C; L/Ni = 10) gives (+)-(S)-3-vinylcyclohexene with 73·5% optical purity in 87% chemical yield when (–)-(R)-N-methyl-N-(1-phenylethylamino)diphenyl-phosphine is used.