DABSO as a SO₂ gas surrogate in the synthesis of organic structures

Abstract

1,4-Diazabicyclo[2.2.2]octane bis(sulfur dioxide), DABCO.SO2, or DABSO, a bench-stable colorless solid, is industrially produced by the reaction of DABCO with the condensed and bubbled sulfur dioxide gas at low temperatures. However,...

Photocatalytic Late-Stage C–H Functionalization

“…As outlined Scheme B, thianthrenium salts ( 77.1 ) can undergo single-electron reduction from the photoexcited * Ir­(ppy) 3 , generating aryl radical species (analogously to Scheme ). Aryl radicals are immediately trapped by SO 2 , generated in situ from DABSO, and deliver S -centered radicals 77.5 . Electron-rich silyl enol ether 77.2 can intercept sulfinyl radical 77.5 to give α-siloxy radical 77.6 , ready to undergo oxidative radical-to-polar crossover to α-siloxy carbenium ion 77.7 .…”

Photocatalytic fluorosulfonylation of aliphatic carboxylic acid NHPI esters

“…DABSO was developed by Santos et al in 1988 13 and was first applied as a novel SO 2 source by Willis and co-workers to deliver aryl aminosulfonamides in 2010. 14 Since then, DABSO has frequently been used as a solid precursor of SO 2 gas in the synthesis of various sulfonyl products, 15 especially arylsulfonyl fluorides in recent years (Scheme 1, I). 16 Unsurprisingly, it can also be used to synthesize aliphatic sulfonyl fluorides.…”

3-Arylsulfonylquinolines from N-Propargylamines via Cascaded Oxidative Sulfonylation Using DABSO

“…Recently, the direct installation of sulfur dioxide (SO 2 ) in organic compounds − through a multicomponent reaction strategy has gained enormous attention in organic synthesis. − Indeed, radical-mediated cascaded insertion of SO 2 is highly advantageous over other known approaches because of the high reactivity of sulfonyl radicals . Among the familiar SO 2 sources, gaseous SO 2 surrogates are generally not recommended for organic reactions due to the handling issues and unmeasurable concentration. , Again, other solid surrogates like sodium dithionites (Na 2 S 2 O 4 ), thiourea dioxide, potassium metabisulfite (K 2 S 2 O 5 ), and DABCO·(SO 2 ) 2 (DABSO) are commonly used. , Due to the air stability and easy handling procedure, DABSO is preferable as the SO 2 source. − However, other solid surrogates have poor solubility in organic solvents. ,, Recently, Waldvogel and Wu groups have individually shown the insertion of SO 2 using photochemical and electrochemical strategies. In addition, oxidative sulfonylation reactions are possible with sulfinic acids, sulfonyl chlorides, sulfonyl hydrazides, etc. , So, the insertion of SO 2 functionalities in organic molecules at ambient conditions via multicomponent reaction strategies can be a topic of interest.…”

“…14 Among the familiar SO 2 sources, gaseous SO 2 surrogates are generally not recommended for organic reactions due to the handling issues and unmeasurable concentration. 15,16 Again, other solid surrogates like sodium dithionites (Na 2 S 2 O 4 ), thiourea dioxide, potassium metabisulfite (K 2 S 2 O 5 ), and DABCO•(SO 2 ) 2 (DABSO) are commonly used. 17,18 Due to the air stability and easy handling procedure, DABSO is preferable as the SO 2 source.…”