<i>N</i>-Bromosuccinimide (NBS) Catalyzed Highly Chemoselective Acetalization of Carbonyl Compounds Using Silylated Diols and Pentaerythritol under Neutral Aprotic Conditions
作者:Babak Karimi、Hassan Hazarkhani、Jafar Maleki
DOI:10.1055/s-2004-837291
日期:——
Various types of carbonylcompounds are efficiently convened to their 1,3-dioxanes and pentaerythritol diacetals by the use of either 1,3-bistrimethylsiloxy propane (A) or 1,3-bistrimethylsilanyloxy-2,2-bistrimethylsilanyloxymethyl propane (D) and a catalytic amount of N-bromosuccinimide (3-10 mol%) under essentially neutral aprotic condition, respectively. A variety of functionalities such as both
A Green Recyclable Poly(4-Vinylpyridine)-Supported Copper Iodide Nanoparticle Catalyst for the Chemoselective Synthesis of Pentaerythritol Diacetals from Aromatic Aldehydes
Poly(4-vinylpyridine)-supported copper(I) iodide nanoparticles have been used as an efficient, green recyclable catalyst for the chemoselective synthesis of pentaerythritol diacetals from aromatic aldehydes and pentaerythritol under solvent-free conditions. This catalyst was reused six times without any loss of its activity.
Novel chiral macrocyclic polyimines with spiro carbon atoms are described. The key feature of the synthesis is the formation of an axially chiral quaternary carbon atom having four constitutionally identical substituents. This is possible either by the freezing of the labile conformation of a spiro-diboronate moiety or by the diastereomeric fitting of a conformationally stable spiro-acetal moiety into
Acetalation of Pentaerithritol Catalyzed by an Al-Pillared Saponite
作者:V. Kannan、K. Sreekumar、A. Gil、M. A. Vicente
DOI:10.1007/s10562-011-0572-8
日期:2011.8
Acetalation of pentaerithritol has been carried out in the presence of an Al-pillared saponite. Several carbonyl compounds were used, including aldehydes and ketones. Yields between 72 and 93% were obtained in all cases, except in the case of veratraldehyde where the carbonyl group was blocked. The high conversion could be explained by diffusion effects of intermediates and electronic effects between the reactants in the transition state. The catalyst was found to be active after three cycles.
MURZA, M. M.;SAFAROV, M. G.;DAVYDOV, A. M.;BAZUNOVA, G. G.
作者:MURZA, M. M.、SAFAROV, M. G.、DAVYDOV, A. M.、BAZUNOVA, G. G.