CBZ6 as a Recyclable Organic Photoreductant for Pinacol Coupling
作者:Hua Wang、Jian-Ping Qu、Yan-Biao Kang
DOI:10.1021/acs.orglett.1c00537
日期:2021.4.16
% CBZ6)-catalyzed reductive (pinacol) coupling of aldehydes, ketones, and imines has been developed. Irradiated by purple light (407 nm) using triethylamine as an electron donor, a variety of 1,2-diols and 1,2-diamines could be prepared. The oxidation potential of the excited state of CBZ6 is established as −1.92 V (vs saturated calomel electrode (SCE)). The relative high reductive potential enables
Isothiourea-Catalysed Sequential Kinetic Resolution of Acyclic (±)-1,2-Diols
作者:Siegfried Harrer、Mark D. Greenhalgh、Rifahath M. Neyyappadath、Andrew D. Smith
DOI:10.1055/s-0037-1610721
日期:2019.8
The isothiourea-catalysed acylative kineticresolution of a range of acyclic (±)-1,2-diols using 1 mol% of catalyst under operationally simple conditions is reported. Significantly, the bifunctional nature of (±)-1,2-diols was exploited in a sequential double kineticresolution, in which both kineticresolutions operate synergistically to provide access to highly enantioenriched products. The principles
A monomeric titanium(III) complex, TiCl3(tmeda)(thf) (1), has been prepared by a reaction of TiCl4 with TMEDA, Zn, and a catalytic amount of PbCl2 in an almost quantitative yield. The solid state structure of 1 is revealed by X-ray crystallographic analysis. The complex 1 couples aromatic aldehydes under mild conditions to give 1, 2-diols in good to excellent yields with high dl-selectivities.
Hydrogen Bonding-Assisted Enhancement of the Reaction Rate and Selectivity in the Kinetic Resolution of <i>d,l</i>
-1,2-Diols with Chiral Nucleophilic Catalysts
作者:Kazuki Fujii、Koichi Mitsudo、Hiroki Mandai、Seiji Suga
DOI:10.1002/adsc.201700057
日期:2017.8.17
An extremely efficient acylative kineticresolution of d,l‐1,2‐diols in the presence of only 0.5 mol% of binaphthyl‐based chiral N,N‐4‐dimethylaminopyridine was developed (selectivityfactor of up to 180). Several key experiments revealed that hydrogen bonding between the tert‐alcohol unit(s) of the catalyst and the 1,2‐diol unit of the substrate is critical for accelerating the rate of monoacylation
The carbon–carbonbond cleavage of 1,2-diols is an important chemical transformation. Although traditional stoichiometric and catalytic oxidation methods have been widely used for this transformation, an efficient and valuable method should be further explored from the views of reusable catalysts, less waste, and convenient procedures. Herein an inorganic-ligand supported iron catalyst (NH4)3[FeMo6O18(OH)6]·7H2O