SYNTHESIS AND PROPERTIES OF 5-(2,3-DIPHENYLCYCLOPROPENYLIDENE)-1,6-METHANO-2(5H)--ANNULENONE (OR 10,11-DIPHENYL-4,9-METHANOQUINAREN-3-ONE). CONTRIBUTION OF HOMOBENZENE STRUCTURE ANNELATED ON QUINAREN-3-ONE

Article abstract of DOI:10.1016/S0040-4039(01)91412-1

The title quinarenone 2 has been prepared and proved that the three-membered ring possesses a larger diatropicity than diphenylcyclopropenone and the seven-membered ring exists in a cycloheptatriene (not norcaradiene) tautomer having a contribution of a homobenzene structure.The rotational barrier about the intercyclic bond of 2 is 13,3 Kcal/mol.