A general electron donor–acceptor complex enabled cascade cyclization of alkynes to access sulfur-containing heterocycles

Abstract

We disclosed a general visible light-promoted and electron-donor-acceptor complex enabled cascade reaction of alkynes via a radical addition/cyclization cascade sequence under photocatalyst-, base-, oxidant- and metal-free conditions. The arylsulfinic acid...

Photocatalyst‐ and Transition‐Metal‐Free Light‐Induced Formation of Carbon‐Chalcogen Bonds

“…Cascade cyclization of alkynes to access sulfurcontaining heterocycles. [83] thesis of 9-sulfenylphenanthrenes under photocatalystfree conditions. [85] Wang group applied a bromoalkyne system with diaminodiphenyl disulfide to synthesize alkynylthioethers 19 c under visible light-induced catalyst-free conditions (Scheme 19).…”

“…Recently, Yang and co‐workers presented a cascade cyclization of alkyne derivatives, promoted by visible light, under conditions devoid of both metals and photocatalysts (Scheme 18). [83] The reaction was initiated through the formation of an EDA complex between 2‐alkynylthioanisole 18 a and arylsulfinate anion 18 b . Upon photo‐irradiation of the EDA complex, a radical anion 18 iii and a sulfinic radical 18 i were generated, with the latter able to resonate into a stable sulfonyl radical 18 ii .…”

Photoinduced Regioselective Sulfonylsulfination of Alkenes

“…Organosulfur compounds are of fundamental significance in modern synthetic and biological chemistry, especially sulfoxides, sulfones, sultines, and sultones, and play a pivotal role in the pharmaceutical, agrochemical, functional materials, and petrochemical industries. They are prominent structural motifs in numerous natural products, bioactive molecules, and pharmaceuticals, and provide crucial intermediates in organic synthesis. − Among the various hitherto developed organosulfur molecules, the structural motif of a two-carbon unit with a sulfone and sultone/sulfinate (sultine analogue) on each carbon has attracted extensive attention, because these frameworks have shown unique chemical and biological properties such as agrochemical fungicides, protease inhibitors, and materials (Figure a). − As such, the development of efficient methods that expand the available C2-linked 1,2-bis-sulfuratom components is of high demand, − and many elegant progress has been established in 1,2-dichalcogenation of carbon–carbon double bond based on visible-light photoredox catalysis, Lewis acid catalysis, and transition metal-catalyzed cross-coupling reactions by Maies, Wu, Jiang, Zhu, Wang, Bi, and others; however, their applications to the synthesis of dichalcogenated molecules typically involve disulfonylation, disulfenylation, thiosulfonylation, and sulfinylsulfonylation with prefunctionalized disulfur transfer reagents (Figure b).…”

Visible Light Promoted Brominative Dearomatization of Biaryl Ynones to Spirocycles

“…Over the past decade, visible light driven photoredox catalysis has gained colossal interest in the exploration of novel transformations employing photocatalyst (PC) to promote the reactions under external oxidant-free or reductant-free conditions . Driven by our prolonged interest in dearomative spiro-cyclization chemistry and newly gained interest in visible light promoted reactions, we explored the possibility of brominative carbannulation of biaryl ynones to form spiro[5.5]-trienones.…”