TBAB-Catalyzed 1,6-Conjugate Sulfonylation of para-Quinone Methides: A Highly Efficient Approach to Unsymmetrical gem-Diarylmethyl Sulfones in Water

Abstract

A highly efficient sulfonylation of para-quinone methides with sulfonyl hydrazines in water has been developed on the basis of the mode involving a tetrabutyl ammonium bromide (TBAB)-promoted sulfa-1,6-conjugated addition pathway. This reaction provides a green and sustainable method to synthesize various unsymmetrical diarylmethyl sulfones, showing good functional group tolerance, scalability, and regioselectivity. Further transformation of the resulting diarylmethyl sulfones provides an efficient route to some functionalized molecules.

Electrochemical Radical δ-H Sulfonylation Reaction for the Synthesis of 4-((Aryl,Arylsul fonyl)methylene)-2,5-Cyclohexadiene Derivatives

“…Third, the radical mode 1,6-addition reactions of p -QMs were also reported by a few research groups (Scheme , previous work c) . Recently, the reactions of p -QMs with some sulfonation reagents (ArSO 2 Na, CF 3 SO 2 Na, and ArSO 2 NHNH 2 ) to give corresponding products with a sulfone moiety (except for CF 3 SO 2 Na) have been reported by the different researchers; however, they were still the 1,6-conjugate addition reaction.…”

Iron-Catalyzed Ring Opening of Cyclopropanols and Their 1,6-Conjugate Addition to p-Quinone Methides

“…HRMS (ESI) spectra were recorded using a Bruker Impact HD quadrupole plus ion trap at the CIF S. P. Pune University. Alkyl-substituted p -QM ( 1z ) was prepared by following literature procedures …”

“…Alkyl-substituted p-QM (1z) was prepared by following literature procedures. 19 General Procedure for the Preparation of p-QMs (1a−1y). In a Dean−Stark apparatus, a mixture of aldehyde (1.0 equiv) and 2,6-ditert-butylphenol (1.0 equiv) in toluene (0.25 M) was placed and Scheme 3.…”

Selective sulfonylation and isonitrilation of para-quinone methides employing TosMIC as a source of sulfonyl group or isonitrile group

“…Traditionally, diarylmethyl sulfones are synthesized by transition-metal-catalyzed deoxy C–S bond-coupling reaction of sodium arylsulfinates with diarylmethanols [ 11 ], C–H functionalization of alkyl sulfones with aryl halides [ 12 ], and via a reductive strategy through nitrogen loss of sulfonyl hydrazones [ 13 – 14 ]. In addition, a sulfa-1,6-conjugated addition reaction [ 15 – 17 ] has also been developed for this purpose. Most of the reported methods are affected by long reaction times and the need for expensive metal catalysts or reagents.…”