Executive Summary : | The sulfonyl group is a widespread motif in pharmaceuticals, agrochemicals and in materials. They are also well known as reaction intermediates. From 1900 to 2016, US-FDA has approved 288 small molecule sulfur-containing drugs. Sulfones and sulfonamides accounts 28% of this. Various sulfur dioxide surrogates including DABCO.(SO2)2 {DABSO}, inorganic sulfites, rongalites and others have been employed for the insertion of ‘SO2’ into small organic molecules. The key advantage these ‘SO2’ surrogates offers is their operational benefit and easy availability over the gaseous and toxic form of sulfur dioxide. Diverse sulfonyl compounds including sulfones and sulfonamides have been prepared starting from the surrogates. Very recently, we have documented a one pot three-component reaction using p-quinone methides, rongalite and alkyl/allyl/aryl halides for the synthesis of various unsymmetrical sulfones. However, there are still some challenges including reactivity and selectivity in this area which need to be addressed. Among the approaches developed, the sulfonylation of unactivated C(sp2)–H bonds and C(sp3)–H bonds with the insertion of sulfur dioxide is very limited (Scheme 2) and most of the reports are known with activation of aryl C-H. In continuation of our interest in sulfone chemistry, the present proposal, we will be exploring use of SO2 surrogates for the insertion of sulfone and sulfonamide functional group into various alkenes/alkynes substrates using photoredox catalysts. |