Oxidative cleavage of α-sulfonyl ketones to carboxylic acids with Ce(NH4)2(NO3)6

Acid-Controlled Access to β-Sulfenyl Ketones and α,β-Disulfonyl Ketones by Pummerer Reaction of β-Keto Sulfones and Sulfoxides

A convenient acid-mediated reaction of β-keto sulfones with sulfoxides under metal-free conditions has been developed, thereby delivering the acid-controlled synthesis of β-sulfenyl ketones and α,β-disulfonyl ketones in good to excellent yields. The mechanism of the transformations has been studied carefully, which suggested the involvement of a radical process in the formation of α,β-disulfonyl ketones.

NH2OH-HCl-Mediated Umpolung α-Methylsulfonylation of α-Sulfonyl Ketones with Methylsulfoxides: Synthesis of α,β-Bis-sulfonyl Arylketones

In this paper, a novel and efficient route for the synthesis of α,β-bis-sulfonyl arylketones via an NH₂OH-HCl-mediated intermolecular umpolung α-methylsulfonylation of α-sulfonyl ketones with methylsulfoxides is described. A plausible mechanism is proposed and discussed. Various reaction conditions for this efficient, one-pot, environmentally friendly transformation were investigated.

Synthesis of β-keto sulfones via a multicomponent reaction through sulfonylation and decarboxylation

A copper(i)-catalyzed synthesis of β-keto sulfones through reaction of aryldiazonium tetrafluoroborates, 3-arylpropiolic acids, sulfur dioxide, and water is realized. This reaction proceeds through a tandem radical process involving sulfonylation and decarboxylation.

Sterically Demanding Oxidative Amidation of α-Substituted Malononitriles with Amines Using O2

An efficient amidation method between readily available 1,1‐dicyanoalkanes and either chiral or nonchiral amines was realized simply with molecular oxygen and a carbonate base. This oxidative protocol can be applied to both sterically and electronically challenging substrates in a highly chemoselective, practical, and rapid manner. The use of cyclopropyl and thioether substrates support the radical formation of α‐peroxy malononitrile species, which can cyclize to dioxiranes that can monooxygenate malononitrile α‐carbanions to afford activated acyl cyanides capable of reacting with amine nucleophiles.

DMSO/I2 mediated C–C bond cleavage of α-ketoaldehydes followed by C–O bond formation: a metal-free approach for one-pot esterification

One-pot I₂/DMSO mediated metal-free C–C bond cleavage of aryl-/heteroaryl- or aliphatic α-ketoaldehydes offering a carboxylic acid followed by esterification is presented.