Harnessing the potential of sulfamidyl radical in photocatalytic synthesis of organosilanes and organogermanes

Abstract

The focus of this thesis is to harness the potential of sulfamidyl radical for the functionalization of Si-H/Ge-H bonds of hydrosilanes/hydrogermanes through hydrogen atom transfer for the photocatalytic synthesis of organosilicon and organogermanium compounds. Firstly, the sulfamidyl radical was generated under visible light-assisted photocatalytic reductive quenching condition by using simple sulfonamide as a precursor for sulfamidyl radical and achieved selective functionalization of Si-H/Ge-H bond over C-H bond of hydrosilanes/hydrogermanes. Moreover, sulfonamides are readily accessible from inexpensive and commercially available sulfonyl chlorides and amines, rendering them cost-effective HAT catalyst. The steric and electronic properties of sulfonamide can be systematically tuned, enabling optimal matching with the varying bond dissociation energies of the Si-H and Ge-H bond of hydrosilanes and hydrogermanes respectively. In addition, a complementary protocol was also developed for the generation of sulfamidyl radical under photocatalytic oxidative quenching condition using N-aminopyridinium salt, enabling the synthesis of organosilicon and organogermanium compounds.