There are only a few reported examples of [,6s ... Published on 01 January 1983. Downloaded by google on 17/02/2016 00:14:45. ... View Article Online / Journal Homepage / Table of Contents for this issue ... Buta-l,3-diene and cycloheptatriene (molar ratio C,H, : C,H,: Et2A1C1: TiCl, = 100: 100: 20: 1, for experimental details see ref. 7) afford mainly 7-endo-vinylbicyclo [4.2.1]- nona-2,4-diene (l), a product of the "6, + ,2,] reaction, accompanied by bicyclo [4.4.1 ...