. Can. J. Chem. 65, 18 10 (1987).Photolysis of 5-(1-and 2-naphthylmethy1)-3-phenylcyclopent-2-ens affords [2 + 21 cycloaddition products, the 7,8-and 5,6-benzo-fused l0-phenyltetracyclo[7.2.1.03~10.04~9]dodeca-5,7-dien-2-ones respectively, in equilibrium with the starting enones. A similar dibenzo-fused photoproduct is formed from the corresponding 9-phenanthrylmethyl substituted cyclopentenone. The photoproducts revert to the respective enones on acid treatment, or pyrolysis, and on photolysis. La photolyse des (naphtyl-1 ou -2 methyl)-5 phenyl-3 cyclopentine-2 ones conduit i des produits de cycloadditions [2 + 21, soit respectivement les benzo-7,8 ou -5,6 phenyl-10 tttracyclo[7.2.1 .03.10.04.9] dodCcadi&ne-5,7 ones-2, qui sont en tquilibre avec les Cnones de depart. Si l'on part de la cyclopent~none correspondante substitute par une phtnanthryl-9 mtthyle, il se forme un photoproduit similaire qui est fusionni i un dibenzo. Par traitement avec des acides, par pyrolyse ou par photolyse, les photoproduits se retransforment dans leurs hones respectives.[Traduit par la revue]In recent publications (1, 3, 4) we have described the photochemical intramolecular cyclisation of 5-ally1 and substituted 5-allylcyclopentenones. In all these cases the reactions were regiospecific, as far as the direction of addition, but in the case of the compounds with cinnamyl side chains there was loss of stereoselectivity of the phenyl substituent. We wished to discover whether aromatic "double bonds" could be incorporated into cycloaddition products and, if so, whether the regiospecificity would be affected. Furthermore, to our knowledge, no example is known where enone adds onto a naphthalene ring although, where two naphthalene rings are linked by a suitable chain, then photoaddition of the two rings is found (5). SvnthesisThe 5-arylmethyl-3-phenylcyclopentenones were synthesised by standard routes (Scheme 1). The ring closure of the diketo esters involves the hydrolysis of the ester and decarboxylation of the keto acid, followed by cyclisation of the resultant 1,5-diketone. In this way, 5-benzyl-, 5-(1-naphthylmethy1)-, 5-(2-naphthylmethy1)-, and 5-(9-phenanthrylmethy1)-3-phenylcyclopentenones (la-d) were prepared.

. Can. J. Chem. 66, 454 (1988).To assess the influence of the conformation of the cyclohexanonc moiety in bicyclo[3.2.l]octan-2-ones on the reactivity for p-enolate rearrangement, the behavior of three derivatives under typical hon~oenolization conditions has been examined for comparison with 3.3-dimethylbicyc~o[3.2.l]octan-2-one (I), which was known to be snloothly converted to the [3.3.0] isomer 2. For this purpose, e1~do-3-tert-butyl-e,~o-3-methylbicyclo[3.2.l]octan-2-onc (8), elldo-9-tert-butyl-exo-9-methyl-exotricyclo[5.3.1 .0',6] undecan-8-one (9), and 9,9-dimethyl -elldo-tricyclo[5.3.1 .0',6] undecan-8-one (10) were prepared and treated with t-BuO-It-BuOH at 2 185OC for prolonged periods. Each is much less reactive than 1. The relative orientations of the carbonyl groups with respect to the sites for p-enolizhtion were determined by molecular mechanics (MM2) calculations. ' H /~H exchange in 9 and 10 was also examined under strongly basic conditions at 185OC. Dans le but d'Cvaluer I'influence de la conformation de la portion cyclohexanone des bicyclo[3.2.l]octanones-2 sur la rCactivitC conduisant a une transposition P-Cnolique, on a examin6 le comportement de trois dCrivCs dans des conditions d'homoCnolisation pour comparer avec le comportement de la dimCthyl-3,3 bicyclo[3.2.l]octanone-2 (I) qui se transforme facilement en son isomkre [3.3.0] (2). A ces fins, on a prCparC la tert-butyl-3-endo mCthyl-3-exo bicyclo[3.2. lloctanone (8), la tert-butyl-9-endo mCthyl-9-endo tricyclo[5.3.1.0'~6]und~canone-8-eso (9) et la dimCthyl-9,9 tricyclo[5.3

. 65, 1557 (1987).Under homoenolization conditions (I-BuO-/I-BuOH/ 185"C), 3,3-dimethylbicyclo[3.2.l]oct-6-en-2-one (5) is converted into six products through three reaction pathways. The major product, 3,3-dimethylbicyclo[3.3.0]octan-2-one, arises by unidirectional p-enolate rearrangement of 5 to the isomeric unsaturated [3.3.0] ketones, which (a) undergo efficient reduction to 2, by single electron transfer, and (b) suffer Haller-Bauer cleavage to two isomeric 2,2-dimethyl-3-cyclopentenylpropanoic acids. In competition with these processes is the reversible conjugate addition of I-BuO-to 5 to furnish the 6-tert-butoxy derivative, which undergoes p-enolate rearrangement to two isomeric ketones. The structures of these products were established primarily from their ' H and I3C magnetic resonance spectra.GREG A. ANTONIADIS, MICHAEL T. M. CLEMENTS, SRIYAWATHIE PEIRIS et J. B. STOTHERS. Can. J. Chem. 65, 1557.Dans des conditions d'homoCnolisation (I-BuO-/I-BuOH/185"C), la dimethyl-3,3 bicyclo[3.2.1]octkne-6 one-2 (5) se transforme en six produits, par le biais de trois voies rCactionnelles. Le produit principal, la dimethyl-3,3 bicyclo[3.3.0]octanone-2, provient d'une transposition unidirectionnelle du p-Cnolate du compost 5 en cetones [3.3.0] insaturees isomkres (a) qui subissent une reduction efficace en 2 par un transfert unique d'electron et (b) qui subissent un clivage de Haller-Bauer pour conduire a deux acides dimethyl-2,2 cyclopentkne-3 yl propanoi'ques isomkres. Ces processus sont en competition avec ['addition conjuguee reversible de l'anion I-BuO-au compose 5 qui conduit au derive tert-butylate-6 qui subit une transposition P-Cnolique conduisant i deux cetones isomkres. Pour determiner les structures, on a principalement fait appel aux spectres de resonance magnetique nucltaire du 'H et du I3c.[Traduit par la revue]

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