oxiranes, and malonitrile has been described. In this transformation, copper acetylide was attacked on oxiranes to form homopropargyl alkoxy‐copper intermediate that was further transferred to 2H‐pyrane skeletons by reaction with malonitrile. We found that the reaction was not productive without hexafluoroisopropanol.
Cationic Rhodium(I)/Bisphosphane Complex-Catalyzed Isomerization of Secondary Propargylic Alcohols to α,β-Enones
作者:Ken Tanaka、Takeaki Shoji、Masao Hirano
DOI:10.1002/ejoc.200700071
日期:2007.6
alcohols to α,β-enones. A kinetic resolution of secondary propargylic alcohols proceeded with moderate selectivity with [Rh((R)-BINAP)]OTf as a catalyst. Mechanistic studies revealed that the isomerization proceeds through intramolecular 1,3- and 1,2-hydrogen migration pathways. The isomerization of propargylic diol derivatives was also investigated, which revealed that 1,4-diketones, furans, and α,β-enones
Mutual Cooperation in the Formal Allyl Alcohol Nucleophilic Substitution and Hydration of Alkynes for the Construction of γ-Substituted Ketones
作者:Kaimeng Huang、Hongkai Wang、Lingyan Liu、Weixing Chang、Jing Li
DOI:10.1002/chem.201600248
日期:2016.5.4
Mutual cooperation in the formal allyl alcohol nucleophilic substitution reaction and hydration of an alkyne has been utilized in the presence of a gold catalyst to give a series of γ‐functionalized ketones with high to excellent yields. This reaction actually involved an intramolecular O−H insertion cyclization of an alkyne to form the dihydrofuran intermediate, which was followed by the nucleophilic
A Convergent General Strategy for the Functionalized 2-Aryl Cycloalkyl-Fused Chromans: Intramolecular Hetero-Diels-Alder Reactions of<i>ortho</i>-Quinone Methides
Five and six: 3,4‐Cyclopentyl‐ and cyclohexyl‐fused 2‐arylchromans could be readily prepared from the intramolecular hetero‐Diels–Alder reactions of the corresponding ortho‐quinone methide (o‐QM) precursors tethered to the styrenes under mild reaction conditions. The products were obtained with good to excellent diastereoselectivity (up to>99:1 dr; see scheme; MOM=methoxymethyl).
Distal Alkenyl C–H Functionalization via the Palladium/Norbornene Cooperative Catalysis
作者:Zhao Wu、Nina Fatuzzo、Guangbin Dong
DOI:10.1021/jacs.9b11479
日期:2020.2.12
A distal-selective alkenyl C-H arylation method is reported through a directedpalladium/norbornene (Pd/NBE) cooperative catalysis. The key is to use an appropriate combination of the directing group and the NBE co-catalyst. A range of acyclic and cyclic cis-olefins are suitable substrates, and the reaction is operated under air with excellent site-selectivity. Preliminary mechanistic studies are consistent
报道了一种通过定向钯/降冰片烯(Pd/NBE)协同催化的远端选择性烯基CH芳基化方法。关键是使用导向基团和NBE助催化剂的适当组合。一系列无环和环状顺式烯烃都是合适的底物,反应在空气下进行,具有优异的位点选择性。初步机制研究与所提出的 Pd/NBE 催化 CH 激活而不是 Heck 途径一致。使用 MeI 和溴乙酸甲酯作为亲电子试剂,在远端烷基化方面也取得了初步成功。