Synthesis of oxacyclic dienes via ring-closing enyne metathesis: Difference in construction of eight-membered rings

Article abstract of DOI:10.1016/j.tetlet.2012.04.107

A series of oxacyclic diene compounds, especially eight-membered products bearing a single oxygen atom which have not been reported previously, were successfully synthesized via ring-closing enyne metathesis using the second-generation Grubbs catalyst. In contrast to the construction of the five-membered rings, completely opposite substrate selectivity that methyl substituted internal alkyne showed much higher reactivity than terminal alkyne was observed in building eight-membered ring derivatives.