2,2′-Biphenyldiol-bridged bis(free base porphyrin): synthesis and chiroptical probing of asymmetric amino alcohols
摘要:
A new type of bis(free base porphyrin) 1, in which two porphyrin units are attached to the 5,5'-positions of the 2,2'-biphenyldiol group, has been synthesized. It exhibits exciton-coupled bisignate circular dichroism (CD) spectra upon interaction with chiral amino alcohols. The chiral information from the stereogenic center of amino alcohols is introduced as a twist of the porphyrin units in 1 via hydrogen bonding interactions, detectable by the signal in the CD spectrum. Based on these findings, it is proposed that 1 should serve as a reporter unit of chiral sensor systems. (c) 2006 Elsevier Ltd. All rights reserved.
Gold-catalyzed direct oxidative coupling reactions of non-activated arenes
作者:Anirban Kar、Naveenkumar Mangu、Hanns Martin Kaiser、Man Kin Tse
DOI:10.1016/j.jorganchem.2008.11.016
日期:2009.2
A general gold-catalyzedoxidative homo- and hetero-coupling of arenes in mild conditions is described. This reaction gives moderate to excellent yield using PhI(OAc)2 as an oxidant. The effects of temperature, solvent, oxidant and concentration of substrate in this process have also been studied in detail. The product identity and distribution as well as the substrate limitation give us insights into