The hydrogen atom transfer reactivity of sulfinic acids

Abstract

Sulfinic acids are characterized to be very good H-atom donors to each of alkyl and alkoxyl radicals. In order to participate in useful radical chain reactions, the sulfonyl radicals must undergo fast propagating reactions to avoid autoxidation, which is surprisingly rate-limited by the reaction of sulfonyl radicals with oxygen.

Amidoalkylation of Sulfonylheteroarenes with Alkylamides through a Radical Chain Mechanism

“…undergoes hydrogen abstraction from 1 to regenerate I (step d ). Step d is likely to be thermodynamically unfavorable, [7] and thus an excess amount of 1 is required to step forward [12] …”

A General Photocatalytic Route to Prenylation

“…Finally, elimination a sulfinyl radical generates the key double bond, providing the prenylated aryl or alkyl product. The sulfinyl radical abstracts a hydrogen atom from an H‐atom donor to generate sulfinic acid, the presence of which has been confirmed by doping experiments (see SI). During the prenylation reaction, we observed that some of 1k underwent a formal 1,3‐rearrangement to form the thermodynamically more stable, linear, and non‐productive prenylated sulfone.…”

Visible Light as the Key for the Formation of Carbon–Sulfur Bonds in Sulfones, Thioethers, and Sulfonamides: An Update

“…Sodium sulfinates can be replaced by sulfinic acids 47, which in a similar way, upon illumination, release the sulfonyl radical thus overcoming through photocatalysis the problems related to autoxidation which limited their application over the past years. 23 Both reagents are bench stable and non-odorous compounds which are easily preparable and commercially available. In 2015, almost contemporary to the group of König, a synthesis of sulfones was proposed by Wang coworkers starting from sulfinic acids.…”

“…Scheme 17 Application of the dual photocatalytic approach to carboxylic acids decarboxylative sulfonylation in the synthesis of bicalutamide Sodium sulfinates can be replaced by sulfinic acids 47, which in a similar way, upon illumination, release the sulfonyl radical thus overcoming through photocatalysis the problems related to autoxidation which have previously limited their application. 23 Both reagents are bench stable and non-odorous compounds and they are easily prepared or commercially available. In 2015, almost contemporary to König, 6 a synthesis of sulfones was proposed by Wang starting from sulfinic acids.…”

“…Scheme23 Visible-light-promoted synthesis of cyclopropane containing -hydroxy sulfones and -cyclopropylstyrenes from sulfonyl chlorides and alkylidenecyclopropanes As observed in Scheme 24, the interaction between Ru II * species and sulfonyl chlorides 57 provides a sulfonyl radical a that can add to the unsaturated moiety. The radical attack generates b.…”