Premium
A Cyclobutadiene Intermediate in the Intramolecular Cycloaddition of 4,15‐Bis(phenylethynyl)[2.2]paracyclophane
Author(s) -
Kubitschke Jens,
Hopf Henning,
Jones Peter G.,
Dix Ina,
Ernst Ludger
Publication year - 2008
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200700702
Subject(s) - cyclobutadiene , chemistry , cyclobutene , photodissociation , intramolecular force , photochemistry , cyclooctatetraene , cycloaddition , bicyclic molecule , ring strain , ring (chemistry) , isomerization , cyclophane , derivative (finance) , double bond , stereochemistry , polymer chemistry , crystallography , organic chemistry , crystal structure , molecule , financial economics , economics , catalysis
The pseudo ‐geminally substituted paracyclophane 4,5‐bis(phenylethynyl)[2.2]paracyclophane ( 13 ) was prepared and its photochemical behaviour in solution was studied. Irradiation with a medium‐pressure mercury lamp converts 13 into two dimers: cyclooctatetraene 14 and bicyclo[4.2.0]octatriene derivative 15 . The structures of both the substrate and the photolysis products were determined by the usual spectroscopic methods and also by X‐ray structural analysis; an unusually long C–C bond of 1.659 Å opposite the double bond in the cyclobutene ring of 15 was found. It is suggested that product formation involves cyclobutadiene 16 as an intermediate. Photolysis of 13 in the presence of pentacarbonyliron furnishes cyclopentadienone complex 19 in quantitative yield. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Accelerating Research
Robert Robinson Avenue,
Oxford Science Park, Oxford
OX4 4GP, United Kingdom
Address
John Eccles HouseRobert Robinson Avenue,
Oxford Science Park, Oxford
OX4 4GP, United Kingdom