6052-46-6Relevant articles and documents
Umpolung Difunctionalization of Carbonyls via Visible-Light Photoredox Catalytic Radical-Carbanion Relay
Wang, Shun,Cheng, Bei-Yi,Sr?en, Matea,K?nig, Burkhard
supporting information, p. 7524 - 7531 (2020/08/05)
The combination of photoredox 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 including CO2 and aldehydes, whereas CF3 radical addition furnishes a wide range of gem-difluoroalkenes through β-fluoride elimination of the generated α-CF3 carbanions. More than 80 substrate examples demonstrate the broad applicability of this reaction sequence. A series of investigations including radical inhibition, deuterium labeling, fluorescence quenching, cyclic voltammetry, and control experiments support the proposed radical-carbanion relay mechanism.
Nickel-Catalyzed Regioselective Cleavage of Csp2-S Bonds: Method for the Synthesis of Tri- and Tetrasubstituted Alkenes
Chen, Jinyang,Chen, Sihai,Xu, Xinhua,Tang, Zhi,Au, Chak-Tong,Qiu, Renhua
, p. 3246 - 3255 (2016/05/19)
We describe here an efficient route for the synthesis of (Z)-vinylic sulfides 3 via the highly regio- and stereoselective coupling of (Z)-1,2-bis(aryl(alkyl)thio)alkenes and Grignard reagents over a Ni catalyst under mild conditions. (Z)-Vinylic sulfides 3 are important intermediates in the synthesis of tri- and tetrasubstituted alkenes that are important construction blocks for drugs and natural products. The directing organosulfur groups (SR) can be converted to diaryl(alkyl) disulfides (RSSR) using H2O2 as oxidant, hence avoiding the waste of sulfur resources. The protocol provides a general method that is highly regio- and stereoselective for the synthesis of a diversity of tri- and tetrasubstituted alkenes.
An operationally simple approach to (E)-α-halo vinyl sulfides and their applications for accessing stereodefined trisubstituted alkenes
Yang, Zhaozhen,Chen, Xiaoyi,Kong, Wei,Xia, Siyuan,Zheng, Renwei,Luo, Fang,Zhu, Gangguo
, p. 2175 - 2185 (2013/04/10)
An operationally simple and practical protocol for the synthesis of (E)-α-halo vinyl sulfides has been achieved via a highly regio- and stereoselective hydrohalogenation of alkynyl thioethers using lithium halides in HOAc or propionic acid at room temperature. It permits the formation of (E)-α-chloro and (E)-α-bromo vinyl sulfides in satisfactory yields with good to excellent stereoselectivities. Moreover, this work results in a new method for the assembly of stereodefined (E)- or (Z)-trisubstituted alkenes featuring the first coupling of the C-X bond of (E)-α-halo vinyl sulfides followed by a subsequent Ni-catalyzed coupling of the C-S bond with Grignard reagents. The Royal Society of Chemistry 2013.
