Generation and [4+2] cycloaddition of 1,6-methano[10]-annulene-3,4-quinodimethane: a novel synthesis of dimethyl 1,6-methanobenzo[3,4-a][10]annulene-13,14-dicarboxylate

A new quinodimethane, 1,6-methano[10]annulene-3,4-quinodimethane (1), was g enerated and trapped by the Diels-Alder reactions with various dienophiles to provide 1,6-methano[10]annelenes 3 fused with a six-membered ring at the 3,4-positions, one of which was derived to a benzene ring analogue 4. (C) 2001 Published by Elsevier Science Ltd.