Catalyst-Controlled Highly Selective Coupling and Oxygenation of Olefins: A Direct Approach to Alcohols, Ketones, and Diketones
作者:Yijin Su、Xiang Sun、Guolin Wu、Ning Jiao
DOI:10.1002/anie.201303917
日期:2013.9.9
Oxygen? That's radical! A method for the direct synthesis of substituted alcohols, ketones, and diketones through a catalyst‐controlled highly chemoselective coupling and oxygenation of olefins has been developed. The method is simple and practical, can be switched by the selection of different catalysts, and employs molecular oxygen as both an oxidant and a reagent.
Nickel-Catalyzed Reductive Benzylation of Aldehydes with Benzyl Halides and Pseudohalides
作者:Farhad Panahi、Marzieh Bahmani、Nasser Iranpoor
DOI:10.1002/adsc.201400970
日期:2015.4.13
benzylation of aromatic and aliphatic aldehydes with benzylic halides is reported using a nickel/zinc catalyst system. In addition to benzylic halides, the first report on the addition of benzylic triflates, acetates, tosylates and tritylates to aldehydes is also presented. By this new method a range of alcohols was synthesized efficiently from aldehydes and benzylic substrates at room temperature in moderate
Nickel-Catalyzed Cross-Coupling of Styrenyl Epoxides with Boronic Acids
作者:Daniel K. Nielsen、Abigail G. Doyle
DOI:10.1002/anie.201101191
日期:2011.6.27
Let's get multicatalytic! A Ni0 catalyst complexed with a biaryldialkyl monophosphine ligand facilitates CC bond formation between styrenylepoxides and aryl boronicacids (see scheme). X‐ray analysis of a catalytically active nickel/ligand complex supports a redox pathway involving CO bond activation. A variety of α‐substituted alcohols were generated with good reaction efficiency by a multicatalytic
A series of unsymmetrical 2,3-diaryl epoxides were hydrogenated under transfer-hydrogenation conditions using the polyurea-encapsulated palladium catalyst [Pd(0)EnCatTM]. The position of the cleaved C-O bond was determined by ¹H NMR analysis of the ring-opened products derived from the epoxide, in which one of the two benzylic methyne protons is deuterated. The ratio of ring-opened products of the unsymmetrically substituted 2,3-diaryl epoxides was affected by the degree of the steric bulkiness on the aromatic ring.
Stable ethers are successfully transformed into secondary alcohols via C–O bond activation using a simple cobalt pincer catalyst. Mechanistic studies indicate the involvement of radical pairs, and their sequential recombination and the subsequent hydrolysis results in the formation of secondary alcohols.