New Intramolecular Five-Endo-Mode Cyclization of Allenyl Aryl Ketones

Article abstract of DOI:10.1246/cl.1994.389

A convenient preparation of allenyl aryl ketones was achieved by the Weinreb-modified Grignard reaction of N-methoxy-N-methylamides with propargylmagnesium bromide.On treatment with BF3*OEt2, the allenyl aryl ketones were converted to methylenebenzocyclopentenones via a new 5-endo-mode cyclization.