Regioselective Benzannulation of Allylic Sulfur Ylides with Ynones: A Rapid Access to Substituted Thioanisoles

The efficiency and selectivity of annulation reactions are often difficult to control in the presence of multiple potential reactive centers, like in case of allylic sulfur ylides (ASY). Here, we describe a novel base mediated [3+3] benzannulation of ASY and readily available alkynones that accomplishes the regioselective formation of multi substituted thioanisoles, highly sought after chemical scaffolds. A new reactivity pattern of ASY has been unearthed, where it acted as both 3C component and sulfur source in benzannulation. Use of handy base, operational simplicity and broad substrate scope are the additional salient features of the conversion.