Nickel(0)-promoted synthesis of tetralin lactones from the co-cyclisation of monoynes and octa-1,7-diynes terminally substituted with ester or amide groups

The co-cyclisation of octa-1,7-diynes with a variety of monoynes mediated by nickel(0) requires ester or amide groups at the terminal positions of the diyne and is subject to steric hindrance about the diyne rather than the monoyne; fused tetralin lactones are the most common products obtained in moderate to good yields. Intramolecular cyclisation of two triynes to the same type of product gives superior yields.