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An efficient novel visible-light photoredox-catalyzed dual carbon–carbon bond cleavage of methylenecyclopropanes and cycloketone oximes for the synthesis of 2-cyanoalkylsulfonated 3,4-dihydronaphthalenes through the insertion of sulfur dioxide is established. This dual cleavage of carbon–carbon bonds involves a radical pathway and goes through a sequence of iminyl radical formation, carbon–carbon bond cleavage, sulfur dioxide insertion, sulfonyl radical addition, another carbon–carbon bond cleavage, and intramolecular cyclization. [ABSTRACT FROM AUTHOR]

A novel visible-light promoted sulfonylation/ipso-cyclization of N-arylpropiolamides with arylamines and DABCO·(SO2)2 to synthesize various sulfonated spiro[4,5]trienones is reported. This sulfonylation/ipso-cyclization reaction proceeds via a radical process and undergoes arylsulfonyl radical formation, sulfonylation, and ipso-cyclization. The experimental results indicate that H2O provides an oxygen atom for the construction of the carbonyl group. [ABSTRACT FROM AUTHOR]

A convenient method for oxidant-promoted radical cascade acylation or decarbonylative alkylation of 1,7-dienes with aldehydes has been established. This method allows for the rapid construction of N-containing polycyclic skeletons in a highly regio- and stereoselective manner. This transformation provides a simple and efficient method for the preparation of a range of tetrahydro-6 H -indeno[2,1- c ]quinolinone derivatives by sequential formation of three new carbon-carbon bonds. Additionally, this radical cascade cyclization can selectively convert aldehydes into aroyl/primary aliphatic acyl radicals and secondary or tertiary alkyl radicals.

Cyclobutanone oximes and their derivatives are pivotal core structural motifs in organic chemistry. Iminyl-radical-triggered C-C bond cleavage of cyclobutanone oximes delivers an efficient strategy to produce stable distal cyano-substituted alkyl radicals, which can capture SO 2 , CO or O 2 to form cyanoalkylsulfonyl radicals, cyanoalkylcarbonyl radicals or cyanoalkoxyl radicals under mild conditions. In the past several years, cyanoalkylsulfonylation/cyanoalkylcarbonyaltion/cyanoalkoxylation has attracted a lot of interest. In this updated report, the strategies for trapping SO 2 , CO or O 2 via iminyl-radical-triggered ring-opening of cyclobutanone oximes are summarized.

A new protocol is herein described for the direct generation of alkylated indolo/benzoimidazo[2,1- a ]isoquinolin-6(5 H )-one derivatives by using Hantzsch esters as alkylation radical precursors using a photoredox/K 2 S 2 O 8 system. This oxidative alkylation of active alkenes involves a radical cascade cyclization process and a sequence of Hantzsch ester single electron oxidation, C-C bond cleavage, alkylation, arylation and oxidative deprotonation.

A visible-light-mediated tandem cyanoalkylsulfonylation/cyclization of alkynoates with cycloketone oxime compounds for the preparation of 3-cyanoalkylsulfonylcoumarins via SO 2 insertion is reported. The difunctionalization of carbon-carbon triple bonds includes a radical mechanism and involves the formation of an iminyl radical, ring-opening of the cycloketone, insertion of SO 2 , addition of the sulfonyl radical to carbon-carbon triple bonds, ipso-cyclization and ester migration.