The pinacol coupling is one of the most significant methods to synthesize vic-diols. The combination of samarium diiodide (SmI2) and samarium metal successfully induces the selective pinacol couplings of not only aromatic aldehydes and ketones but also aliphatic ones in the presence of trimethylchlorosilane (Me3SiCl) in 1,2-dimethoxyethane (DME). DME is the most suitable solvent for the reduction system
Iron-catalyzed Pinacol Coupling of Aryl Ketones with a Phenyltitanium Reagent: A New Type of Catalytic Reaction
作者:Tamio Hayashi、Keigo Sasaki
DOI:10.1246/cl.2011.492
日期:2011.5.5
A reaction of aryl ketones with phenyltitanium triisopropoxide ([PhTi(Oi-Pr)3]) in the presence of [Fe(acac)3] as a catalyst (1 mol %) gave the corresponding pinacols in high yields. The catalytic cycle of this process involves an iron-catalyzed disproportionation of [PhTi(Oi-Pr)3] into biphenyl and a low-valent titanium species.
Zinc-Mediated Efficient and Selective Reduction of Carbonyl Compounds
作者:Tirtha Mandal、Snehasish Jana、Jyotirmayee Dash
DOI:10.1002/ejoc.201700887
日期:2017.9.8
Simple yet unknown! Aldehydes and ketones can be easily reduced to the corresponding alcohols with Zn/NH4Cl, which is used for pinacol coupling reactions. Chemoselective reduction of aldehydes in the presence of ketones is achieved. Isatins can be efficiently reduced at the C3 position.
Novel diastereoselective photo-induced pinacolcouplingreactions of acetophenones by using triethylamine and chiral tertiary amines as electron donating co-sensitizers were studied. Various influence factors including solvents, substituents, and chiral amines on both the diastereoselectivity and yield were examined. The diastereoselectivities were enhanced in supramolecular systems of cyclodextrins
aromatic carbonylcompounds were carried out using an 80% [BMIM][BF4]–H2O mixture as the electrolytic medium. The corresponding diols were obtained in good to excellent yields with moderate diastereoselectivity. The stereoselectivity can be explained using the strongly-bound ion-pairs formed between the imidazolium cation and the radical anions of the carbonylcompounds. The ionicliquid replaces both