DABCO-Bis(sulfur dioxide), DABSO, as a Convenient Source of Sulfur Dioxide for Organic Synthesis: Utility in Sulfonamide and Sulfamide Preparation

Abstract

The charge-transfer complex generated from the combination of DABCO and sulfur dioxide, DABSO, is a bench-stable colorless solid suitable for use in organic synthesis as a replacement for gaseous sulfur dioxide. The complex can be combined with Grignard reagents to form sulfinates, which can then be converted in situ to a series of sulfonamides. Alternatively, reaction with anilines and iodine leads to the formation of a series of sulfamides. Cheletropic addition between DABSO and 2,3-dimethylbutadiene provides the corresponding sulfolene.

Novel fluorine-18 labeled 5-(1-pyrrolidinylsulfonyl)-7-azaisatin derivatives as potential PET tracers for in vivo imaging of activated caspases in apoptosis

“…We found that the use of just one equiv t-BuLi is sufficient and improves the reaction sequence in terms of reproducibility, atom efficiency and higher yields. 30 Furthermore, we were able to 31 This bench-stable colorless solid is easier to handle and allows a fully controlled dosing of SO 2 equivalents. After formation of the arylsulfinate by reacting DABSO with the organolithium compound the sulfonyl chloride was prepared with NCS.…”

The Development and Application of Sulfur Dioxide Surrogates in Synthetic Organic Chemistry

“…[65] This process has been exploited by Kopka and co-workers in their investigation of lithium-halogen exchange reactions. [66] Alternatively, sulfonamides can also be accessed through a two-step procedure, using bleach (sodium hypochlorite) to form the sulfonamide directly from a mixture of the in situ derived sulfinate and free amine (Scheme 11 B).…”

“…X-ray structure and photograph reproduced with permission from the American Chemical Society. [65] Scheme 11. Two procedures for sulfonamide synthesis exploiting DABSO-derived sulfinates.…”

“…[71] Finally, although not reactions with organometallics, DABSO can also be used to access sulfamides and sulfolenes in easy-to-perform adaptations of the corresponding procedure with SO 2 gas. [65] …”

Palladium‐Catalyzed Three‐Component Diaryl Sulfone Synthesis Exploiting the Sulfur Dioxide Surrogate DABSO

“…[14] We have recently developed DABSO (1), which is a solid, bench-stable complex formed between 1,4-diazabicyclo-[2.2.2]octane (DABCO) and two sulfur dioxide molecules, [15] as an easy-to-handle surrogate for sulfur dioxide gas (Scheme 2). We have demonstrated its use in known reactions of sulfur dioxide, [16] as well as in a novel palladium-catalyzed aminosulfonylation of aryl, heteroaryl, and alkenyl halides to yield medicinally important sulfonamides. [17] Herein, we report on a three-component convergent synthesis of a broad range of aryl, heteroaryl, and alkenyl sulfones, employing palladium catalysis and DABSO (Scheme 2).…”