title: Catalytic [2+2+1] Synthesis of Fused Thiophenes Using Thiocarbonyls as Sulfur Donors.
abstract: The use of N-(p-chlorophenyl)methylbenzoxazole-2-thione as a sulfur-atom donor enables the catalytic [2+2+1] cycloaddition of diynes in wet DMF at 80 °C when open to air, thus affording diverse fused thiophenes with good yields and wide functional-group compatibility. A plausible mechanism, involving a cationic ruthenacycle intermediate, was also proposed on the basis of several control experiments.
authors.affiliation: Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical Sciences, Nagoya University, Chikusa, Nagoya, 464-8601, Japan.
authors.forename: Kazuma
authors.initials: K
authors.lastname: Matsui
authors.affiliation: Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical Sciences, Nagoya University, Chikusa, Nagoya, 464-8601, Japan.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Shibuya
authors.affiliation: Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical Sciences, Nagoya University, Chikusa, Nagoya, 464-8601, Japan.
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Yamamoto
keywords: alkynes; cycloaddition; reaction mechanisms; ruthenium; sulfur heterocycles