Metal catalysis in organic reactions. Part 4. Stereospecificity in the dimerization and cyclotrimerization of chiral alk-1-ynes

Abstract

The reaction of (S)-3-methylpent-1-yne with tri-isobutylaluminium in the presence of bis-N-methylsalicylideneaminenickel has been studied. Depending on the experimental conditions, the alkyne was converted mainly into (E)-(3S,7S)-3,7-dimethyl-4-methylenenon-5-ene or 1,3,5-tris-[(S)-1-methylpropyl]benzene. Both dimerization and cyclotrimerization occurred without racemization. In this context the stereospecificity of other catalysed cyclotrimerizations has been examined.