Reactions of αω-dodecatrienediylnickel with dimethyl acetylenedicarboxylate and methyl propiolate

Abstract

The reaction of αω-dodecatrienediylnickel with dimethyl acetylenedicarboxylate at 0 °C yields approximately equal amounts of twelve- and fourteen-membered ring products, whereas, at –78 °C, 80% of the product has the larger ring. The reaction of αω-dodecatrienediylnickel with methyl propiolate yields exclusively methyl 12-vinylcyclododeca-1,4,8-trienecarboxylate. A similar insertion reaction of dimethyl acetylenedicarboxylate into a bis(η-allyl)-nickel complex, derived from αω-dodecatrienediylnickel and allene, has been shown to give a reasonable yield of dimethyl 14-methylenecyclohexadeca-1,4,8,12-tetraene-1,2-dicarboxylate.