Tetrahedron

Rhodium (1) catalysed regiospecific cyclisation of 1, 6-enynes to methylenecyclohex-2-enes

R Grigg, P Stevenson, T Worakun

Index: Grigg, Ronald; Stevenson, Paul; Worakun, Tanachat Tetrahedron, 1988 , vol. 44, # 15 p. 4967 - 4972

Full Text: HTML

Citation Number: 44

Abstract

1, 6-Enynes are cyclised regiospecifically by 5 mol% of Wilkinson's catalyst [(Ph3P) 3RhCl] in acetonitrile at 80° C to give the corresponding methylene cyclohex-2-enes usually in good yield (62–83%). Terminal substitution on either the alkene or alkyne moieties effectively suppresses the reaction. 4-Benzoylaza-and 4-benzylaza-hepta-1, 6-enynes are similarly cyclised to 5-methylene-1, 2, 5, 6-tetrahydropyridines in 20–28% yield. The mechanism of ...