An enantioselective alkoxycarbonylation-amination cascade process of terminalallenes with CO, methanol, and arylamines has been developed. It proceeds under mild conditions (room temperature, ambient pressure CO) via oxidative Pd(II) catalysis using an aromatic spiroketal-based diphosphine (SKP) as a chiral ligand and a Cu(II) salt as an oxidant and affords a wide range of α-methylene-β-arylamino
Palladium-Catalyzed Oxidative Carbonylative Coupling of Arylallenes, Arylboronic Acids, and Nitroarenes
作者:Hui-Qing Geng、Jin-Bao Peng、Xiao-Feng Wu
DOI:10.1021/acs.orglett.9b02925
日期:2019.10.18
In this Letter, a palladium-catalyzed multicomponent procedure for the selective synthesis of α-substituted α,β-unsaturated ketones has been developed. With readily available allenes, arylboronicacids, and nitroarenes as the substrates, the reaction proceeds selectively to the desired α-substituted enones. Notably, no manipulation of carbon monoxide gas is needed here, and Mo(CO)6 has been applied
A silver(I) catalyzed regioselective trifluoromethylation of allenes using Langlois's salt (NaOSOCF3) is demonstrated. This transformation enables direct expedient access to α‐trifluoromethylated acroleins, which are valuable synthons for a number of pharmaceuticals and agrochemicals containing vinyl‐CF3 moieties. Versatility of this trifluoromethylation method has been established with good yield
Fluorinative Rearrangements of Substituted Phenylallenes Mediated by (Difluoroiodo)toluene: Synthesis of α-(Difluoromethyl)styrenes
作者:Zhensheng Zhao、Léanne Racicot、Graham K. Murphy
DOI:10.1002/anie.201706798
日期:2017.9.11
(difluoroiodo)toluene in the presence of 20 mol % BF3⋅OEt2 to yield α‐difluoromethyl styrenes. This unprecedented reaction was entirely chemoselective for the internal allene π bond, and showed remarkable regioselectivity during the fluorination event. Substituted phenylallenes, phenylallenes possessing both phenyl‐ and α‐allenyl substituents, and diphenylallenes were investigated, and good functional‐group
Chlorination of phenylallene derivatives with 1-chloro-1,2-benziodoxol-3-one: synthesis of <i>vicinal</i>-dichlorides and chlorodienes
作者:Zhensheng Zhao、Graham K Murphy
DOI:10.3762/bjoc.14.67
日期:——
Allyl and vinyl chlorides represent important structural motifs in organic chemistry. Herein is described the chemoselective and regioselective reaction of aryl- and α-substituted phenylallenes with the hypervalent iodine (HVI) reagent 1-chloro-1,2-benziodoxol-3-one. The reaction typically results in vicinal dichlorides, except with proton-containing α-alkyl substituents, which instead give chlorinated