Photocycloaddition of chalcones to yield cyclobutyl ditopic cyclophanes
作者:Francesca R Cibin、Nicoletta Di Bello、Giancarlo Doddi、Vincenzo Fares、Paolo Mencarelli、Elio Ullucci
DOI:10.1016/j.tet.2003.10.026
日期:2003.12
The intramolecular photocycloaddition of chalcones to give cyclobutanes has proved to be a fast and convenient method to shrink a cyclophane ring to a tricyclic system, in order to prepare potential ditopic receptors. X-Ray results confirm the previously indicated structure for the cyclobutanes 2a (n=1, m=1), in which the cyclization occurs by a head-to-head syn ring closure. NMR results indicate that the same process occurs for the cyclobutanes 2b (n=2, m=2) and 2c (n=1, m=3). (C) 2003 Elsevier Ltd. All rights reserved.
Synthesis of a ditopic cyclophane based on the cyclobutane ring by chalcone photocycloaddition
作者:Francesca R Cibin、Giancarlo Doddi、Paolo Mencarelli
DOI:10.1016/s0040-4020(03)00475-7
日期:2003.5
The intramolecular photocycloaddition of chalcones to give cyclobutanes has proven to be a fast and simple method to shrink a cyclophane ring to a tricyclic system, in order to prepare potential ditopic receptors. In particular, the chalcone 1, having dioxyethylene chains as spacers, is converted in high yield to the cyclobutane 2. NOESY spectroscopy indicates that the formation of 2 occurs by a head-to-head