Cyclizations of ω-Allenyl Organometallic Reagents.

Allenyl organometallic reagents of type R2CCCH(CH2)nCH2M undergo cyclization at the central allenic carbon for n = 2 (M = Li) and at the near allenic carbon for n = 3 (M = CuCNLi) to provide cyclopentane systems; little cyclization, was observed for the n = 4 systems (M = Li, CuCNLi).