On the reactivity of μ2-acetylenes coordinated to cobalt : II. Regiospecifity of the carbonylation of internal acetylenes

The μ₂-carbonyl- μ₂-spiro(2,3-substituted-2-butene-4-olide-4-ylidene)bis(tricarbonylcobalt)(CoCo), Co₂(CO)₇(C₄O₂R¹R²), “lactone” complexes were prepared from internal acetylenes. It was found that the reaction is regiospecific; in the products from an asymmetric internal alkyne the sp carbon atom which had the higher value of the ¹³C NMR chemical shift (δ) occupied the 2-, while that with the lower δ value the 3-position of the lactone ring. fa]For Part I, see ref. 1. Some results or this work were presented at the Annual Meeting of the Hungarian Chemical Society (MKE Vegyészkonferencia), Aug. 23–26, 1977. Debrecen. Abstracts (Elöadások összefoglalói) p. 156