Asymmetric Synthesis and Characterization of Chiral 2,2'-Diamino-3,3'-diethoxycarbonyl-8,8'-diphenyl-1,1'-biazulene

Author: Chen Arh-Hwang   Yen Hsiu-Hang   Kuo Yu-Chen   Chen Wen-Zhang  

Publisher: Taylor & Francis Ltd

ISSN: 0039-7911

Source: Synthetic Communications, Vol.37, Iss.17, 2007-01, pp. : 2975-2987

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

rac-2,2'-Diamino-3,3'-diethoxycarbonyl-8,8'-diphenyl-1,1'-biazulene was synthesized from diethyl 2-aminoazulene-1,3-dicarboxylate and was optically resolved into two enantiomers of S-form and R-form. The enantioselective oxidative couplings with two chiral amines [(-)-sparteine and (R)-(+)-α-methylbenzylamine] and ferric chloride catalyst, and the asymmetric couplings with two chiral oxovanadium(IV) complexes of ethyl 2-amino-4-phenylazulene-1-carboxylate, easily yielded chiral 2,2'-diamino-3,3'-diethoxycarbonyl-8,8'-diphenyl-1,1'-biazulene. Therefore, the introduction of two phenyl groups at the 8- and 8'-postions of each azulene ring using phenyl magnesium bromide via an addition-oxidation-decarboxylation mechanism resulted in 1,1'-biazulene forming a chiral C2 axis.