O₂-mediated C(sp²)–X bond oxygenation: autoxidative carbon–heteroatom bond formation using activated alkenes as a linkage

Abstract

Autoxidative carbon-heteroatom bond formation using activated alkenes as a linkage is described. Heteroatom (O, S) nucleophiles could be transformed into different kinds of valuable b-keto compounds via an O 2 -mediated C(sp 2 )-X bond oxygenation process, without using any external organic oxidants or metal catalysts.

Sulfinic Acids in Organic Synthesis: A Review of Recent Studies

“…The Lei group [5a] elaborated the oxygen‐mediated oxysulfonylations of activated alkenes in the presence of pyridine. The in situ generated radical adduct was captured by oxygen to form peroxy radicals, which underwent protonation by pyridinium to give β‐keto sulfones.…”

Advances in Oxosulfonylation Reaction

“…[81][82][83][84] Lei group is a pioneer in this field. In 2015, the Lei group [65] revealed a simple oxosulfonylation method via oxygen triggered C(sp 2 )À X bond oxygenation process. No metal catalyst or external oxidants were used in this reaction.…”

“…In light of its extensive efficacies, numerous protocols of oxosulfonylation such as metal-catalyzed oxosulfonylation, [46][47][48][49][50][51][52][53][54][55] organophotocatalyzed oxosulfonylation, [32,[56][57][58] metal-based photocatalyzed oxosulfonylation, [59][60][61] catalyst free photo-induced oxosulfonylation [62][63][64] etc have been developed. Very recently, oxygen triggered oxosulfonylation methods [65][66][67][68][69][70][71][72] show great interest among synthetic organic chemists.…”

K2S2O8‐Mediated Oxysulfonylation of Vinyl Azides with Sodium Sulfinates to Access β‐Keto Sulfones in Water

“…A variety of methods have been reported toward the synthesis of β‐keto sulfones including the oxidation of β‐keto sulfides, [12] the alkylation of sodium sulfonates with α‐halo ketones or α‐tosyloxy ketones, [13–14] cross‐coupling of diazo compounds with aldehydes [15] as well as oxosulfonylation of alkenes and alkynes with different sulfone sources [16–18] . Among them, oxosulfonylation of alkenes and alkynes has drawn significant attention of chemists because it provides a powerful platform for rapid formation of β‐keto sulfones in a flexible and efficient manner, such as copper‐catalyzed oxysulfonylation of alkenes with dioxygen and sulfonylhydrazides, [19] iron‐catalyzed difunctionalization of alkenes with dioxygen and sulfinic acids, [20] AgNO 3 /K 2 S 2 O 8 catalyzed aerobic oxysulfonylation of alkenes with sodium arenesulfinate, [21] iron‐catalyzed oxidative sulfonylation of enol acetates with sulfonylhydrazides (Scheme 1a), [22] sulfated tungstate mediated oxysulfonylation of styrenes with sulfonylhydrazides, [23] TBHP mediated oxysulfonylation of alkenes with sulfonyl chloride, [24] dioxygen triggered oxysulfonylation of α‐halogenated alkenes with phenylsulfinic acids ( Scheme 1b) [25] and oxysulfonylation of phenylacetylene with benzenediazonium tetrafluoroborate, and DABSO, [26] and visible‐light mediated oxosulfonylation of alkenes with sulfonyl hydrazides [27] or phenylsulfinic acids, [28] alkynes with sulfonylhydrazides, [29] and enol silyl ether with sulfonyl halides (Scheme 1c) [30] . Recently, oxosulfonylation of vinyl azides has been investigated to achieve β‐keto sulfones (Scheme 1d) [31,32] and N‐unsubstituted enaminosulfones [33,34] .…”

“…Vinyl azides are very significant synthons and are commonly used as a radical acceptor to construct various molecular skeleton, such as β‐sulfonyl enamines, [35] α‐trifluoromethylated ketones, [36] β‐keto sulfones, [25] phenanthridines, [37,38] nitriles, [39] quinolines, [40] pyridines, [41] imidazo[1,2‐ a ]‐pyridine, [42] α‐tetralone [43] and O‐phthalimide oxime [44] . We envisage that the newly formed sulfonyl radicals that generated from sodium sulfinates 2 may attack the C−C double bond of vinyl azide 1 and subsequently the radical addition occurs to furnish the iminyl radical with the release of N 2 on account of the unique chemical properties of the azide group.…”