Photosensitizer-free synthesis of β-keto sulfones via visible-light-induced oxysulfonylation of alkenes with sulfonic acids

Oxysulfonylation of Alkynes with Sodium Sulfinates to Access β-Keto Sulfones Catalyzed by BF3·OEt2

An efficient and operationally simple method for the synthesis of β-keto sulfones through the BF3·OEt2-promoted reaction of alkynes and sodium sulfinates is developed. With its facile and selective access to the targets, it features good functional group compatibility, mild conditions, easily available starting materials, and good yields. Notably, the reaction does not require metal catalysts or chemical reagents with pungent odors.

Persulfate-Promoted Carbamoylation/Cyclization of Alkenes: Synthesis of Amide-Containing Quinazolinones

The incorporation of amide groups into biologically active molecules has been proven to be an efficient strategy for drug design and discovery. In this study, we present a simple and practical method for the synthesis of amide-containing quinazolin-4(3H)-ones under transition-metal-free conditions. This is achieved through a carbamoyl-radical-triggered cascade cyclization of N3-alkenyl-tethered quinazolinones. Notably, the carbamoyl radical is generated in situ from the oxidative decarboxylative process of oxamic acids in the presence of (NH4)2S2O8.

A visible-light-mediated cascade reaction of quinoxalin-2(1H)-ones, alkenes, and sulfinic acids

A photocatalytic three-component cascade reaction of quinoxalin-2(1H)-ones, alkenes, and sulfinic acids under metal-, strong oxidant-, and external photocatalyst-free conditions was developed. The reaction was performed at room temperature using air as a green oxidant. Various sulfonated quinoxalin-2(1H)-ones were obtained in satisfactory yields with good functional group compatibility. The preliminary study showed that the current transformation was enabled by the formation of an electron donor-acceptor (EDA) complex between quinoxalin-2(1H)-ones and sulfinic acids.

Organic Sulfinic Acids and Salts in Visible Light-Induced Reactions

Sulfinic acids and their salts are a useful source of sulfur-containing structures. Photocatalysis of these compounds with visible light enables to achieve various transformations under mild conditions. This review summarizes visible-light-induced reactions of sulfinic acids and their salts. It is organized by reaction type and brief discussions on plausible reaction mechanisms for typical transformations are presented.

1 Introduction

2 Sulfonylation Reactions

2.1 Sulfonylation of Alkenes

2.2 Sulfonylation of Alkynes

2.3 Sulfonylation of Arenes

2.4 sp3 C–H Functionalization

3 Desulfonylation Reactions

4 Sulfenylation Reactions

4.1 Sulfenylation of Heteroarenes

4.2 Sulfenylation of Carbonyl Chlorides

5 Conclusions