Silver-catalyzed direct spirocyclization of alkynes with thiophenols: a simple and facile approach to 3-thioazaspiro[4,5]trienones

Abstract

A new and convenient silver-catalyzed direct oxidative spirocyclization of alkynes with thiophenols is described. This methodology provides a simple and practical approach to various 3-thioazaspiro[4,5]trienones in moderate to good yields with high atom efficiency and excellent functional

Metal Free Sulfonylative Spirocyclization of Alkenyl and Alkynyl Amides via Insertion of Sulfur Dioxide

“…[5] Indeed, the recent years have seen enormous efforts towards the synthesis of functionalized azaspiro [4,5]-trienones via cascade ipso-spirocyclization of N-arylpropiolamides, involving either electrophilic activation [6] or radical addition. [7] This strategy was efficiently exploited to introduce a variety of functional groups on the azaspiro [4,5]-trienone framework. In sharp contrast, only a handful of reports exist for the synthesis of azaspiro [4,5]-decanes via cascade cyclization.…”

Recent Advances in the Construction of Spiro Compounds via Radical Dearomatization

“…However, this protocol is restricted with arylalkynes bearing the para ‐methoxy substituent on the aryl rings. Almost at the same time, Wei and Wang's group achieved a silver‐catalyzed oxidative spirocyclization of N ‐arylpropiolamides without leaving group (methoxy) on the para ‐position of aryl rings, and the additional H 2 O provided the oxygen in the products (Scheme 6b) [19a] . Very recently, this splendent approach toward 3‐thiolated spiro[4,5]trienones was also established by Sun and Guo with the irradiation of one halogen tungsten lamp, in which using Pd nanoparticle as an efficient, environmentally friendly and recyclable catalyst (Scheme 6c) [19b] .…”

Sustainable C–H activation approach for palladium-catalyzed, regioselective functionalization of 1-methyl-3-phenyl quinoxaline-2(1H)-ones in water

“…The most common method employed for the construction of the quinoxaline framework is based on the condensation of 1,2-diaminobenzene with 1,2-dicarbonyl equivalents. 26 However, these methods suffer from several drawbacks such as pre-functionalized reaction partners, multiple steps, labor-intensive and time-consuming process, and limited substrate scope. These drawbacks can be easily eliminated by transition metal-catalyzed direct installation of functional groups on quinoxaline-2(1 H )-one (Scheme 1).…”