A novel Fe-catalyzed olefin hydroamination with aryldiazo sulfones for accessing alkylarylazo compounds has been successfully developed. Aryldiazo sulfones are used as radical acceptors, and N–N double bonds will be regenerated when an arene sulfonyl group leaves. The reaction features mild reaction conditions and a broad substrate scope, allowing access to many azo compounds that would be difficult
Formation of an Endoperoxide upon Chromium-Catalyzed Allylic Oxidation of a Triterpene by Oxygen
作者:Abbie Chung、Matthew R. Miner、Kathleen J. Richert、Curtis J. Rieder、K. A. Woerpel
DOI:10.1021/jo502344x
日期:2015.1.2
chromium-catalyzed allylic oxidation of triterpene 1 with O2 and N-hydroxyphthalimide (NHPI, 5 equiv) formed endoperoxide 2 in 76% yield at ambient temperature. Unlike standard allylic oxidations, this oxidation is catalytic in chromium because oxygen, not the chromium reagent, is the oxidant. This oxidation is sensitive to the precise structure of the substrate. The endoperoxide is only formed if ring A is unsaturated
Electrocatalytic Ketyl-Olefin Cyclization at a Favorable Applied Bias Enabled by a Concerted Proton–Electron Transfer Mediator
作者:Joseph Derosa、Pablo Garrido-Barros、Jonas C. Peters
DOI:10.1021/acs.inorgchem.2c00839
日期:2022.5.2
atom to organic substrates; however, direct application of CPET in the context of C–Cbondformation beyond homocoupling is underexplored. We report herein the expansion of electrocatalytic CPET (eCPET) using a Brønsted base-appended cobaltocene mediator ([CpCoCpNMe2][OTf]) with keto-olefin substrates that undergo cyclization subsequent to ketyl radical generation via eCPET. Using acetophenone-derived
newly formed stereocenters. When iron-catalyzed borrowing hydrogen from allylic alcohols was combined with a stereocontrolled organocatalytic oxa-Michael addition, a wide array of chiral tetrahydropyrans were efficiently prepared. The reaction could be performed in a diastereoselective manner from pre-existing stereocenters or enantioselectively from achiral substrates. The key to success was the reactivity
The amino-Heck cyclization process has been applied into a range of gamma,delta-unsaturated ketone O-diethylphosphinyloximes 1 and delta,epsilon-unsaturated ketone O-diethylphosphinyloximes 7. Under the specific catalytic conditions developed by us, these substrates were found to preferentially undergo the 6-endo cyclization to give the formation of 2-substituted pyridines 3 and substituted methylpyridines 8, respectively, in moderate to good yields. Besides, several interesting aspects on the effects of phosphinyl groups, solvents, bases and molecular sieves on the regioselectivity of the cyclization of 1 have also been realized.