Umpolung Difunctionalization of Carbonyls via Visible-Light Photoredox Catalytic Radical-Carbanion Relay
作者:Shun Wang、Bei-Yi Cheng、Matea Sršen、Burkhard König
DOI:10.1021/jacs.0c00629
日期:2020.4.22
catalysis with the Wolff–Kishner (WK) reaction allows the difunctionalization of carbonyl groups by a radical-carbanion relay sequence (photo-Wolff–Kishner reaction). Photoredox initiated radical addition to N-sulfonylhydrazones yields α-functionalized carbanions following the WK-type mechanism. With sulfur-centered radicals, the carbanions are further functionalized by reaction with electrophiles
A base‐promoted three‐component coupling of carbon dioxide, amines, and N‐tosylhydrazones has been developed. The reaction is suggested to proceed via a carbocation intermediate and constitutes an efficient and versatile approach for the synthesis of a wide range of organic carbamates. The advantages of this method include the use of readily available substrates, excellent functional group tolerance
NNNifty targets: In a straightforward copper‐mediated synthesis of 1,4‐disubstituted and 1,4,5‐trisubstituted 1,2,3‐triazoles, readily available aniline and N‐tosylhydrazone substrates underwent cyclization through CN and NN bond formation (see scheme; Piv=pivaloyl, Ts=p‐toluenesulfonyl). This method enables the preparation of 1,2,3‐triazoles with high efficiency under mild conditions without the
Palladium-Catalyzed Cross-Coupling Reactions of Electron-Deficient Alkenes with<i>N</i>-Tosylhydrazones: Functional-Group-Controlled CC Bond Construction
作者:Huanfeng Jiang、Wei Fu、Huoji Chen
DOI:10.1002/chem.201202051
日期:2012.9.17
palladium‐catalyzed cross‐coupling reaction of electron‐deficient alkenes with N‐tosylhydrazones, which affords diverse CC bonds resulting from the functional‐group‐controlled effect, is reported (see scheme). These cascade transformations present remarkable stereoselectivity and a high synthetic potential. The presence of water substantially promotes both reaction routes.