Iodine-mediated aminosulfonylation of alkenyl sulfonamides with sulfonyl hydrazides: synthesis of sulfonylmethyl piperidines, pyrrolidines and pyrazolines
作者:Zhong-Qi Xu、Wen-Bo Wang、Lin-Chuang Zheng、Lin Li、Lili Duan、Yue-Ming Li
DOI:10.1039/c9ob01847f
日期:——
aminosulfonylation of alkenyl sulfonamides was reported. Using iodine as the catalyst, TBHP as the oxidant, and sulfonyl hydrazides as the sulfonyl radical sources, a variety of sulfonylmethyl piperidines, pyrrolidines and pyrazolines were obtained in moderate to excellent yields.
An asymmetric synthesis of 5-halomethyl pyrazolines and isoxazolines which bear a tertiary stereocenter by catalytic halocyclization of β,γ-unsaturatedhydrazones and ketoximes is described. By using Brønsted acids of anionic chiral Co(III) complexes as catalysts, a variety of chiral 5-halomethyl pyrazolines and isoxazolines were obtained in good yields with high enantioselectivities (up to 99% yield
BF<sub>3</sub>·OEt<sub>2</sub>-mediated cyclization of β,γ-unsaturated oximes and hydrazones with <i>N</i>-(arylthio/arylseleno)succinimides: an efficient approach to synthesize isoxazoles or dihydropyrazoles
作者:Wei Yu、Shichao Yang、Pei-Long Wang、Pinhua Li、Hongji Li
DOI:10.1039/d0ob01388a
日期:——
A highly efficient BF3·OEt2-mediated cyclization of β,γ-unsaturatedoximes and tosylhydrazones with N-(arylthio/arylseleno)succinimides has been established for the construction of N-heterocycles in a one-step manner. This metal-free cyclization provides direct access to isoxazoles and dihydropyrazoles in good to excellent yields at room temperature. The mechanistic experiments support the formation
Ambient-Light-Promoted Perfluoroalkylative Cyclization of β,γ-Unsaturated Hydrazones: Synthesis of Perfluoroalkylated Pyrazolines
作者:Jing-miao Yu、Chun Cai
DOI:10.1002/ejoc.201701201
日期:2017.11.2
An ambient‐light‐promoted, metal‐free strategy for the direct perfluoroalkylativecyclization of β,γ‐unsaturated hydrazones is reported. This radical process has wide functional‐group tolerance, is performed under mild reaction conditions, and is operationally simple. The perfluoroalkylatedpyrazoline products are obtained in good to excellent yields. TMG = 1,1,3,3‐tetramethylguanidine.
Iodine(<scp>iii</scp>)-mediated intramolecular sulfeno- and selenofunctionalization of β,γ-unsaturated tosyl hydrazones and oximes
作者:Jing-Miao Yu、Chun Cai
DOI:10.1039/c7ob02892j
日期:——
A cascade radical cyclization/sulfenylation or selenylation of β,γ-unsaturatedhydrazones and oximes was realized under mild conditions with phenyliodine(III) diacetate (PIDA) as the sole oxidant, leading to the construction of diversely functionalized heteroatom-containing pyrazoline and isoxazoline derivatives. This metal-free radical process is suggested to encompass a sequential C–N/O and C–S/Se