Syntheses of Donor–Acceptor-Functionalized Dihydroazulenes
作者:Søren Lindbæk Broman、Martyn Jevric、Andrew D. Bond、Mogens Brøndsted Nielsen
DOI:10.1021/jo4020326
日期:2014.1.3
properties relies on ready access to new derivatives via efficient synthetic protocols. The central DHA core is conveniently prepared in a four-step synthesis starting from acetophenone and tropylium substrates. Here, the outcome of this reaction as a function of the nature of the substituent group on the phenyl unit of acetophenone is investigated in detail. A wide variety of functional groups (nitro, cyano
functionalizing the seven-membered ring of the DHA/VHF photochromicsystem via a Suzuki cross-coupling was developed. Kinetic studies reveal that direct attachment of an aromatic moiety on the seven-membered ring strongly affects the thermal back reaction. By the introduction of an anilino group, pH control of both the photochromic and thermochromicproperties was obtained. Furthermore, it was possible to switch