Application of a novel chromophoric reagent, 2,2′-binaphthyl-3,3′-dicarbonyl cyanide, to the absolute configuration determination of chiral secondary alcohols
3′-dicarbonyl cyanide possessing two reaction sites was designed and synthesized as a new chromophoric reagent for exciton-coupled circular dichroism (ECCD), which is more effective in determination of the absolute stereochemistry of the target chiral alcohols than 2,2′-binaphthyl-3-methoxycarbonyl-3′-carbonyl cyanide, which contains only one reaction site. The CD spectra of the 2,2′-binaphthyl diesters
Rhodium(I)-Catalyzed Regiospecific Dimerization of Aromatic Acids: Two Direct CH Bond Activations in Water
作者:Hang Gong、Huiying Zeng、Feng Zhou、Chao-Jun Li
DOI:10.1002/anie.201500220
日期:2015.5.4
2,2′‐Diaryl acids are key building blocks for some of the most important and high‐performance polymers such as polyesters and polyamides (imides), as well as structural motifs of MOFs (metal–organic frameworks) and biological compounds. In this study, a direct, regiospecific and practical dimerization of simple aromaticacids to generate 2,2′‐diaryl acids has been discovered, which proceeds through
Induced circular dichroism in chiral N-methyl amides possessing an achiral binaphthyl chromophore and its application to absolute configuration determination of aliphatic chiral amines
Induced circulardichroism (ICD) was observed in binaphthyl N-methyl amides of chiral primary amines. The CD spectra showed split curves centered at 225 nm. A good correlation was found between the sign of the exciton chirality of the binaphthyl derivative and the absolute configuration of the original amine. Furthermore, the screw sense of the two naphthyl groups in the most stable conformer obtained
Bisoxazoline ligands with an axial-unfixed biaryl backbone: the effects of the biaryl backbone and the substituent at oxazoline ring on Cu-catalyzed asymmetric cyclopropanation
The synthesis of novel C-symmetric bisoxazoline ligands with an axial-unfixed biaryl backbone and different substituents at the oxazoline ring is reported. The diastcreomer equilibrium of these ligands in solution and their complexation behavior with the copper(I) ion were Studied. Their application in Cu-catalyzed cyclopropanation of styrene, with diazoacetate, was carried out and the effects of the biaryl backbone and the substituent on the oxazoline ring in the catalysis were examined. The best result was obtained with the ligand having a 1,1'-binaphthyl backbone and a t-butyl group on the oxazoline ring, which afforded 89% de and 96% de for the trans- and cis-products of the above asymmetric cyclopropanation reaction, respectively. (c) 2006 Elsevier Ltd. All rights reserved.
125. Polycyclic aromatic hydrocarbons. Part XXVIII. Dibenzfluorenes