Synthetic exploration of sulfinyl radicals using sulfinyl sulfones

Abstract

Sulfinyl radicals – one of the fundamental classes of S-centered radicals – have eluded synthetic application in organic chemistry for over 60 years, despite their potential to assemble valuable sulfoxide compounds. Here we report the successful generation and use of sulfinyl radicals in a dual radical addition/radical coupling with unsaturated hydrocarbons, where readily-accessed sulfinyl sulfones serve as the sulfinyl radical precursor. The strategy provides an entry to a variety of previously inaccessible linear and cyclic disulfurized adducts in a single step, and demonstrates tolerance to an extensive range of hydrocarbons and functional groups. Experimental and theoretical mechanistic investigations suggest that these reactions proceed through sequential sulfonyl and sulfinyl radical addition.

The Sulfinylsulfonation of alkynes for β‐Sulfinyl alkenylsulfone

“…Xu et al reported a thiosulfonates of aryl alkynes to deliver (E)‐(β)‐arylthiolvinyl sulfones exclusively [7] . Despite these advances, thiosulfonylation of alkynes involving the formation of C−SO 2 and another C−SO bond simultaneously has only one example [8d] . Building on our continuous interest in the difunctionalization of alkynes, [8,4c,5a] we here reported the sulfinylsulfonation of alkynes using sodium sulfinate and TMSCl, affording a simple and efficient method to access the β‐sulfinyl alkenylsulfone products (Figure 1B).…”

“…During preparation of this manuscript, our group also reported a related sulfinylsulfonation of alkyne, utilizing sodium sulfinate/CH 3 COCl for radical generation. However, this condition didn't tolerate nucleophilic groups such as OH, NH 2 and COOH [8d] …”

Temperature controlled di- and monosulfonylation of propargyl alcohols with sodium sulfinates: switchable access to (E)-allyl, vinyldisulfones and propargyl sulfones

“…5 Given the highly synthetic and pharmaceutical importance of these compounds, the development of mild and efficient approaches to access these sulfones remains a topic of great interest among organic chemists. 6 2,3-Disulfonylpropenes, which contain both the vinyl sulfone and the allyl sulfone structural units, have emerged as versatile synthons in organic synthesis and medicinal chemistry. Although methodologies for the construction of vinyl sulfones and allyl sulfones have been well developed, respectively, to date, protocols for directly accessing disulfonyl compounds, 7 as well as propargyl sulfones, 8 from alkynes are quite rare (Fig.…”

Fluoromethylsulfinyl radicals: spectroscopic characterization and photoisomerization via intramolecular hydrogen shift

“…9 Aside from the involvement in atmospheric chemistry, sulfinyl radicals are useful intermediates in synthetic sulfur chemistry for their broad applications in assembling valuable sulfoxide compounds. 10 Among sulfur-centered radicals, the prototypical alkylsulfinyl radical CH 3 SO was detected in the O 2 -oxidation of DMS. 6a Its molecular structure and reactivity have been the focus of comprehensive experimental and computational studies.…”