β-Sulfonylation of α-bromoenals enabled by N-heterocyclic carbene catalysis

Abstract

An N-heterocyclic carbene (NHC)-catalyzed three-component tandem β-sulfonylation/esterification of α-bromoenals was developed.

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

“…N -Heterocyclic carbene (NHC-37) catalyzed the three-component β-sulfonylation-esterification of β-bromoenals and sodium sulfinates with alcohols for the synthesis of functionalized sulfonyl esters ( Scheme 232 ). 341 The Du group used a variety of 3-(substituted phenyl)-2-bromoenals with electron-withdrawing or electron-donating groups at different positions to afford the corresponding products in good to high yields. Subsequently, aliphatic 2-bromoenals were also applicable, giving rise to sulfone esters in moderate yields.…”

N-Heterocyclic Carbene-Mediated Carbon–Sulfur Bond-Forming Reactions

“…Sodium sulfinate can be used as the nucleophile in the NHC-catalyzed LUMO activation of α-bromo-α,β-unsaturated aldehydes (Figure 14). In 2019, Du and colleagues 61 disclosed an NHC-catalyzed three-component tandem β-sulfonylation/ esterification reaction for asymmetric construction of C−S bonds. This protocol provides a simple and efficient method to synthesize various functionalized alkyl sulfone ester 71.…”

Enantioselective Synthesis of Dihydrothiopyranones via NHC-Catalyzed [3 + 3] Annulation of 2-Bromoenals with β-Oxodithioesters

“…In this context, we envisioned that the use of β-oxodithioesters as bisnucleophiles for intercepting the α,β-unsaturated acylazoliums could result in the formation of either dihydropyranones or dihydrothiopyranones depending on the ease of final cyclization either from the oxygen or the sulfur center. Moreover, compared to the synthesis of oxygen and nitrogen heterocycles, the synthesis of sulfur heterocycles has received limited attention using NHC catalysis . Herein, we report the NHC-catalyzed regioselective and enantioselective [3 + 3] annulation of 2-bromoenals with β-oxodithioesters resulting in the synthesis of dihydrothiopyranones, where the reaction was initiated by the formation of chiral α,β-unsaturated acylazoliums (Scheme C).…”