Benzannulation of Triynes Initiated by an Alder-Ene Reaction and Subsequent Trifluoro­methylthiolate Addition

A new benzannulation
reaction with accompanied trifluoro­methyl­thiolation
is described. This benzannulation can generate a range of trifluoro­methyl­thiolated
benzolactams and benzolactones from 1,3,8-triynes and a stoichiometric
amount of AgSCF3 at 90 °C through an initial Alder-ene
reaction, 1,4-addition of AgSCF3, and a series of bond-reorganization
processes that include double bond migration, 6π-electrocyclization,
and a [1,3]-H shift. For certain substrates containing a triisopropylsilyl
(TIPS) group, the final [1,3]-H shift-interrupted products, were obtained.