Stereoselective Vicinal Difunctionalization of Alkynes through a Three‐Component Reaction of Alkynes, Sodium Sulfinates, and Togni Reagent

Abstract

Stereoselective vicinal difunctionalization of alkynes through trifluoromethylation and sulfonylation via a three‐component reaction of alkynes, sodium sulfinates, and Togni reagent under catalyst‐ and additive‐free conditions has been realized. This reaction proceeds at room temperature in dimethyl sulfoxide (DMSO), providing (E)‐β‐trifluoromethylvinyl sulfones in moderate to good yields. The advantages of this tandem radical process include extremely mild conditions, excellent stereoselectivity, and easy experimental operation.magnified image

Metal–Free Radical Thiocyanatosulfonation of Terminal Alkynes in Aqueous Medium

“…Among those, radical-involved vicinal difunctionalization of alkynes by a sulfone radical represents as a powerful method for building polysubstituted vinyl sulfones via a one-step operation (Scheme ). Examples are halosulfonation, hydrosulfonation, selenosulfonation, aminosulfonylation, phenoxysulfonylation, and carbosulfonylation . Despite these advances, the development of an efficient path for synthesizing thio-substituted vinyl sulfone scaffold remains elusive (Scheme ).…”

Synthesis and applications of sodium sulfinates (RSO2Na): a powerful building block for the synthesis of organosulfur compounds

“…A wide range of ( E )-β-trifluoro-methyl vinyl sulfones were obtained in moderate to good yields with excellent stereoselectivity by using various terminal alkynes, different benzenesulfinates, heteroarenesulfinate or alkanesulfinates and Togni reagent ( Scheme 235 ). 343 The internal alkyne, phenylpropyne, was employed for the synthesis of tetrasubstituted vinylsulfones in low yield with excellent stereoselectivity.…”

Recent advances in transition-metal-free trifluoromethylation with Togni's reagents

“…In 2017, the Wu group reported the stereoselective preparation of (E)-β-trifluoromethylvinyl sulfones 86 via the vicinal difunctionalization of alkynes with sodium sulfinates 85 and Togni's reagent 2 (Scheme 18). 27 This transformation features a wide reaction scope and good functional-group tolerance. The results of mechanistic studies indicated that a SET process taking place between Togni's reagent 2 and sodium sulfonates 85 would produce a CF 3 radical and the sulfonyl radical 88.…”