Synthesis of natural products and related compounds using enyne metathesis

Since the molybdenum and ruthenium carbene complexes 1a and 1b were discovered by Schrock and Grubbs in 1990 and 1992, synthetic organic chemistry has progressed with the use of these complexes as the catalyst for olefin metathesis. It was found that the ruthenium carbene complex was also effective for enyne metathesis, which occurs between an alkene and an alkyne. Intramolecular enyne metathesis gives various cyclic compounds having a 1,3-diene moiety and cross-metathesis of an alkene with an alkyne is a useful method for the synthesis of a compound having a diene moiety. Furthermore, dienyne metathesis, ROM of cycloalkenynes or tandem reactions of enyne metathesis have been developed. Using these various enyne metatheses, complicated natural products have been synthesized via novel routes. The syntheses of natural products and related compounds using enyne metathesis are described.