DIELS-ALDER REACTIONS OF ARYLETHENES - SYNTHESIS OF SOME [5]PHENACENES AND FLUORENOANTHRACENES

A one-pot high yielding route to 3,4-dihydro-1-(2H)-anthracenone (9) b ased oft high pressure Diels-Alder reaction is described. The synthesi s of 3,4-dihydro-1-vinylphenanthrene (1) and 3,4-dihydro-1-vinylanthra cene (2) is reported. A new synthetic two-step approach to [5]phenacen es and fluorenoanthracenes has been developed. It is based on the Diel s-Alder reaction of arylethenes 1 and 2 with benzyne (13), 1,4-benzoqu inone (14), 1,4-naphthoquinone (15) and inden-1-one (17) and on the ar omatization of the cycloadducts. Structure analysis of the reaction pr oducts by H-1 and C-13-NMR spectroscopy is presented. (C) 1998 Elsevie r Science Ltd. All rights reserved.