An efficient one‐pot N‐alkylation of benzimidazole and benzotriazole from carbonyl compounds and tosylhydrazide has been accomplished via copper powder‐catalyzed N—H bond insertion affording N‐alkylated products in good yields. The reaction can tolerate a wide range of carbonyl compounds, such as aryl, alkyl, heterocyclic and α,β‐unsaturated ketones, and aldehydes.
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
Direct Aryloxylation/Alkyloxylation of Dialkyl Phosphonates for the Synthesis of Mixed Phosphonates
作者:Hai Huang、Johanna Denne、Chou‐Hsun Yang、Haobin Wang、Jun Yong Kang
DOI:10.1002/anie.201802082
日期:2018.5.28
A strategy for the direct functionalization strategy of inertial dialkyl phosphonates with hydroxy compounds to afford diverse mixed phosphonates with good yields and functional‐group tolerance has been developed. Mechanistic investigations involving both NMR studies and DFT studies suggest that an unprecedented highly reactive PV species (phosphoryl pyridin‐1‐ium salt), a key intermediate for this
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.