A novel protocol for the synthesis of α-aryl nitriles has been successfully achieved via a copper-catalyzed cyanation of N-tosylhydrazones employing thiocyanate as the source of cyanide. The features of this method include a convenient operation, readily available substrates, low-toxicity thiocyanate salts, and a broad substrate scope.
A formal [4 + 2] cycloaddition of N-tosylhydrazones with ortho-quinone methides was developed, affording the facile synthesis of diverse 1,3-oxazine derivatives under mild conditions. In this transformation, N-tosylhydrazones are used as a 1,2-dipole synthon under base-free conditions. Moreover, the substrate scope is broad, and the products are formed with high diastereoselectivities in most of the
One-Pot Acid-Catalyzed Ring-Opening/Cyclization/Oxidation of Aziridines with <i>N</i>-Tosylhydrazones: Access to 1,2,4-Triazines
作者:Lorène Crespin、Lorenzo Biancalana、Tobias Morack、David C. Blakemore、Steven V. Ley
DOI:10.1021/acs.orglett.7b00101
日期:2017.3.3
described. The process involves an efficient nucleophilic ring opening of the aziridine, giving access to a wide range of aminohydrazones, isolated with excellent yields. A “one-pot” procedure, combining the ring opening with a cyclization and an oxidation step, allows the preparation of diversified triazines in good yields.
Direct Synthesis of Propen-2-yl Sulfones through Cascade Reactions Using Calcium Carbide as an Alkyne Source
作者:Lei Gao、Zhenrong Liu、Xiaolong Ma、Zheng Li
DOI:10.1021/acs.orglett.0c01915
日期:2020.7.2
A simple method for the construction of propen-2-yl sulfones through cascadereactions of calcium carbide with arylsulfonylhydrazones using copper as a mediator is described. The salient features of this protocol are the use of readily available and easy-to-handle alkyne source, broad substrate scope, open-air condition, and simple operation procedure.
Addition of carbon nucleophiles to aldehyde tosylhydrazones of aromatic and heteroaromaticcompounds is reported. New observations have been made wherein alkylative reduction is observed in some cases whereas alkylative fragmentation is noticed in others. These findings are exploited in the synthesis of the useful alkaloid piperine and its analogs.