Generation of Diazomethyl Radicals by Hydrogen Atom Abstraction and Their Cycloaddition with Alkenes
作者:Yong‐Liang Su、Kuiyong Dong、Haifeng Zheng、Michael P. Doyle
DOI:10.1002/anie.202105472
日期:2021.8.16
pyrazolines from α-diazo compounds and conjugated alkenes is reported. The direct hydrogen atom transfer (HAT) process of α-diazo compounds promoted by the tert-butylperoxy radical generates electrophilic diazomethyl radicals, thereby reversing the reactivity of the carbon atom attached with the diazo group. The regiocontrolled addition of diazomethyl radicals to carbon-carbon double bonds followed by intramolecular
In Situ Generation of Nitrilimines from Aryldiazonium Salts and Diazo Esters: Synthesis of Fully Substituted Pyrazoles under Room Temperature
作者:Ying Shao、Hao Zheng、Junfeng Qian、Xiaobing Wan
DOI:10.1021/acs.orglett.8b00750
日期:2018.4.20
A novel one-pot synthesis for fully substituted pyrazoles has been well developed via the in situ generation of nitrilimines from aryldiazonium salts and diazo esters and a subsequent cycloaddition with 1,3-dicarbonylcompounds. High yields, mild conditions, wide substrate scope, and operational simplicity are the significant advantages of this methodology.
Rhodium-Mediated Stereoselective Polymerization of “Carbenes”
作者:Dennis G. H. Hetterscheid、Coen Hendriksen、Wojciech I. Dzik、Jan M. M. Smits、Ernst R. H. van Eck、Alan E. Rowan、Vincenzo Busico、Michele Vacatello、Valeria Van Axel Castelli、Annalaura Segre、Erica Jellema、Tom G. Bloemberg、Bas de Bruin
DOI:10.1021/ja058722j
日期:2006.8.1
stereoselective polymerization of "carbenes" from ethyl diazoacetate (EDA) to give high molecular mass poly(ethyl 2-ylidene-acetate) is described. The mononuclear, neutral [(N,O-ligand)M(I)(cod)] (M = Rh, Ir) catalytic precursors for this reaction are characterized by (among others) single-crystal X-ray diffraction. These species mediate formation of a new type of polymers from EDA: carbon-chain polymers functionalized
The synthesis of cyclic polymer is an important topic in polymer chemistry. Herein, we report a one-step method to prepare cyclic polypyrazoles. Monomers with two functional groups, diazo and alkyne, were synthesized and polymerized via 1,3-diploar cycloaddition in bulk under heating without any catalyst. Polypyrazoles with molecular weights in the range of 3800-4400 g/mol and yields in the range of