Mercury in Organic Chemistry. 26. Synthesis of Heterocycles via Intramolecular Solvomercuration of Aryl Acetylenes

Article abstract of DOI:10.1021/ja00327a026

A number of ortho substituted aryl acetylenes, o-CH3XC6H4YC<*>CR (X=O, S, CO2; Y=-, CO), have been observed to undergo facile intramolecular solvomercuration with mercuric acetate in acetic acid to afford the corresponding benzofuran, benzothiophene, isocoumarin, and chromone organomercuric chlorides, after aqueous sodium chloride workup.The aryl acetylenes m-XC6H4YCH2C<*>CR (X=H, Y=O, R=CH3; X=CH3O, Y=CH2, R=n-C3H7) undergo similar cyclizations to yield mercurated 2H-1-benzopyrans and 1,2-dihydronaphthalenes.The mercuration and subsequent carbonylation of o-R¹OC6H4C<*>CR² 1=Si(t-Bu)Me2, R²=CH3; R¹=CH3, R²=o-C6H4OCH3> has provided a new approach to the coumarin and coumestan ring systems.