Cs2CO3-Mediated Regio- and Stereoselective Sulfonylation of 1,1-Dibromo-1-alkenes with Sodium Sulfinates

Abstract

A highly selective synthesis of (Z)-1-bromo-1-sulfonyl alkenes via Cs2CO3-promoted sulfonylation of 1,1-dibromo-1-alkenes with sodium sulfinates is described. Notably, using excess amounts of Cs2CO3 and sodium sulfinate in such a reaction regenerated the parent aldehyde. Interestingly, the reaction of 1-(2,2-dibromovinyl)-2-nitrobenzene in the presence of sulfinates and Cs2CO3 produced isatin. The Sonogashira cross coupling of synthesized (Z)-1-bromo-1-sulfonyl alkenes with phenylacetylene gave selectively the corresponding sulfonylalkynyl alkenes.

Cascade synthesis of 2,4-disulfonylpyrroles by the sulfonylation/[2 + 3]-cycloaddition reactions of gem-dibromoalkenes with arylsulfonyl methyl isocyanides

“…By assuming the following sulfonylation, we treated the resulting acetylene with sodium p -toluenesulfinate (TsNa) as the tosyl source based on our previously related study. 17 Similarly, we found vinyl sulfone B as the only product, which in continuation, reacted with TosMIC in optimal conditions furnishing compound 3c in 80% yield.…”

“…Inspired by our previously developed conditions, 17 we started our survey by the cycloaddition of 1-bromo-2-(2,2-dibromovinyl) benzene (1a) 20 and TosMIC (2a) under Cs 2 CO 3 condition (2 equiv.) in DMSO at 100 C. Two different routes were envisageable for the reaction (Scheme 2).…”

“…As our ongoing effort to explore the novel synthetic application of 1,1-dibromoalkenes, we have previously investigated the reaction of this alkenes with two reagents of alkyl isocyanides and sodium sulfinates, which in the former, 3-(hetero)arylpropynamides furnished from a palladium-catalyzed cross-coupling reaction, 16 and the latter involved a sulfonylation to yield the desired 1-bromo-1-sulfonylalkenes. 17 gem -Dibromo-1-alkenes, which can be easily generated from the treatment of aldehydes or ketones with CBr 4 /PPh 3 , 18 can act as an alternative resource of activated alkene and alkyne moieties. 19 Encouraged by these findings, we envisaged that arylsulfonyl methyl isocyanides might react with 1,1-dibromoalkenes as a dual functional reagent, both as a [1,3]-dipolar and as a sulfonyl source in a cascade process.…”

Advances in Vinyl Sulfone Catalyzed Synthesis: Methods, Mechanisms and Perspectives

“…[88] These processes do not require the addition of metallic or nonmetallic catalysts, lighting, or electrification conditions, and several reactions do not require the use of organic solvents. [99][100][101][102][103][104][105][106] A pure E-isomer of (E)-α-fluorinated arylvinyl sulfones obtained in the presence of potassium hydroxide only was reported by Fang and coworkers (Scheme 27). [107] The reaction of trifluoromethyl α-fluorinated arylsulfonyl gem-diols and aryl aldehydes in THF for 6 h at room temperature gave a final yield of trisubstituted (E)-α-fluorinated arylvinyl sulfones of approximatley 97 %.…”

“…Researchers have developed methods to obtain vinyl sulfone structural products in moderate to excellent yields only under acidic or alkaline conditions [88] . These processes do not require the addition of metallic or nonmetallic catalysts, lighting, or electrification conditions, and several reactions do not require the use of organic solvents [99–106] …”