First Experimental Evidence of an Intramolecular H Bond between Aliphatic Cl and Aromatic C–H
作者:Xiaoyun Hu、Zixing Shan、Vadim A. Soloshonok
DOI:10.1021/cg201219g
日期:2012.1.4
The first example of an intramolecular H bond between aliphatic Cl and aromatic C H was observed in the crystal of C-2-symmetric (4R,5R)-4,5-bis(diphenylchloromethyl)-1,3,2-dioxathiolane 2-oxide. In this case one Cl atom is engaged in H-bonding with two ortho-C H groups in the axial and equatorial phenyl planes, with the recorded distances of 2.562 angstrom and 2.804 angstrom, respectively. The observed angle for Ca-H-Cl is 108.41 degrees and that. for C-q-H-Cl is 96.53 degrees.
Synthesis of a novel sterically hindered chiral cyclic phosphoric acid derived from l-tartaric acid and application to the asymmetric catalytic Biginelli reaction
A novel sterically hindered chiral cyclic phosphoric acid derived from L-tartaric acid was designed and synthesized based on highly regioselective cyclosulfitation of chiral 1,1,4,4-tetraphenylbutanetetraol. The asymmetric Biginelli reaction catalyzed by this newly synthesized chiral phosphoric acid was examined, and enantioselectivities up to 99% ee was obtained. (C) 2016 Elsevier Ltd. All rights reserved.