allyl ethyl carbonates with isocyanides in the presence of a catalytic amount of Pd(OAc)2 provided ketenimines through β‐hydride elimination of the allyl imidoylpalladium intermediates. The insertion of the isocyanide into the π‐allyl Pd complex proceeded via an unusual η1‐allyl Pd species. The resulting ketenimines were hydrolyzed to β,γ‐unsaturated carboxamides during purification by flash column chromatography
作者:Huan‐Ming Huang、Peter Bellotti、Constantin G. Daniliuc、Frank Glorius
DOI:10.1002/anie.202011996
日期:2021.2
Carbonyl propargylation has been established as a valuable tool in the realm of carbon–carbon bond forming reactions. The 1,3‐enyne moiety has been recognized as an alternative pronucleophile in the above transformation through an ionic mechanism. Herein, we report for the first time, the radical carbonyl propargylation through dual chromium/photoredox catalysis. A library of valuable homopropargylic
Kinetic Resolution of Neopentylic Secondary Alcohols by Cu–H-Catalyzed Enantioselective Silylation with Hydrosilanes
作者:Zaneta Papadopulu、Martin Oestreich
DOI:10.1021/acs.orglett.0c03943
日期:2021.1.15
A nonenzymatic kineticresolution of sterically congested alcohols having a quaternary carbon atom in the β-position is reported. The catalyst system CuCl/NaOtBu/(R,R)-Ph-BPE together with a 3,5-xylyl-substituted tertiary hydrosilane enable enantioselective silylation of the hydroxy group. Several alcohols are obtained with good to excellent selectivity factors, and there are no other known straightforward
报道了在β位具有季碳原子的空间拥挤的醇的非酶动力学拆分。催化剂体系CuCl / NaO t Bu /(R,R)-Ph-BPE与3,5-二甲苯基取代的叔氢硅烷一起使羟基的对映选择性硅烷化成为可能。获得了具有良好至优异的选择性因子的几种醇,并且没有其他已知的直接方法可访问这些基序。
Radical alkylation of <i>para</i>-quinone methides with 4-substituted Hantzsch esters/nitriles <i>via</i> organic photoredox catalysis
作者:Qing-Yan Wu、Qing-Qiang Min、Gui-Zhen Ao、Feng Liu
DOI:10.1039/c8ob01641k
日期:——
functionalized phenols via radical alkylation of para-quinone methides under transition-metal-free conditions. The reaction is external oxidant free and performed at ambient temperature uponvisiblelight irradiation, allowing the access to various desired products in satisfactory yields. The readily available 4-alkyl-1,4-dihydropyridines serve as the effective alkylradicalprecursors.
A highly enantioselective α‐ketol rearrangement has been developed. In the presence of a chiral Cu‐bisoxazoline complex, achiral β‐hydroxy‐α‐dicarbonyls were isomerized to chiralα‐hydroxy‐β‐dicarbonyls and their bicyclic derivatives in excellent yields and enantioselectivities. Enantioenriched 2‐acyl‐2‐hydroxy cyclohexan‐1‐ones, dihydroxyhexahydrobenzofuranones, and dihydroxyhexahydro‐cycloheptafuranones