Divergent pathways in the photochemical reactions of benzonitrile

Photo-additions of Naphthalene Derivatives with Substituted Ethylenes: Influence of Methoxy- and Cyano-substituents on the Products

“…The present study has shown that this type of addition can also occur with 2-methoxy-and 2-cyanonaphthalene, if appropriate ethylenic substrates are used. It has also recently been reported that 2-cyanonaphthalene and tetramethylethylene add to form a cyclobutane on irradiation (24). Inspection of structures 1, 2, 4, and 5 reveals that the following directive effects appear to be operating.…”

Photochemical cycloadditions of benzonitrile to alkenes. Factors controlling the site of addition

“…Since then we have conducted a thorough examination of the reaction mixtures for products of this type, and have examined the reac-tions of 1 with a number of other alkenes in order to delineate precisely the combination of structural features necessary to result in reaction at the cyano group. The first six alkenes (2)(3)(4)(5)(6)(7) belong in the former category, group A, whereas the remainder (8-14) belong in the latter, group B. Brief inspection reveals that, in order for reaction at the cyano group to predominate, either four alkyl groups, or two alkyl and one alkoxy group, must be located on the doubly bonded carbons.…”

“…Brief inspection reveals that, in order for reaction at the cyano group to predominate, either four alkyl groups, or two alkyl and one alkoxy group, must be located on the doubly bonded carbons. The dramatic difference caused by a single methyl group is illustrated by the divergent results obtained with 2,3-dimethyl-2-butene (7), with which reaction of 1 occurs exclusively at the cyano group, and 2-methyl-2-butene (8), in which over 90% of the products result from addition to the benzene ring. The reaction of 1 with alkenes 4 and 13 illustrates the same striking difference caused by one alkyl group.…”

“…2,3-Dimethyl-2-butene. Irradiation through Vycor of hexane solutions of 1 with a two-to tenfold excess of 2,3dimethyl-2-butene (7) until 50% of 1 was consumed gave two products (Scheme I): 2,5-dimethyl-3-phenyl-4-azahexa-2,4-diene (15; 66% based on unrecovered 1), and its valence isomer, 2-phenyl-3,3,4,4-tetramethyl-l-azetine (16; 8%). The structure of azadiene 15 was deduced from its spectral properties, which include NMR singlets at 7.84, 8.08, 8.15, and 8.32, indicative of methyls on vinyl carbons, and was established conclusively by its rapid hydrolysis by cold aqueous acid to isobutyrophenone and acetone.…”

Aroylation of carbanions derived from N-(diphenylmethyl)arylmethanimines. A synthesis of 4-aroyloxy-2-azabuta-1,3-dienes

“…phenyl-2-azabuta-1,3-diene (4b): 3.548, 73% as yellow crystals; m.p. 178-180 "C; 6,3.76 (3 H, s, MeO), 3.83 ( 1273, 420 (22), 419 (66), 404 (21), 403 (64), 373 (20), 166 (21), 165 (56) 268 (E 37630) and 384 (9756) nm; m/z 584 ( l % ) , 449 (18), 434 (26), 433 (loo), 166 (6), 165 (17)…”