Factors influencing the reaction-mode selectivity and regiochemistry of intermolecular photocycloaddition reactions of ethenes to polysubstituted benzenes

✍ Scribed by S. Al-Qaradawi; A. Gilbert; D. T. Jones

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 843 KB
• Volume: 114
• Category: Article
• ISSN: 0165-0513
• DOI: 10.1002/recl.19951141112

✦ Synopsis

Abstract

The photoreactions of the methylbenzonitriles; 2,3‐, 2,4‐, 2,6‐, 3,4‐, and 3,5‐ benzonitriles; and 2′‐ and 4′‐ methoxyacetophenones with cyclopentene and ethyl vinyl ether have been investigated. Meta photocycloaddition is the major process for the benzonitriles with cyclopentene, and regiochemical features reflect the influence of polar factors along the reaction pathway. The enol ether yields ortho cycloadducts exclusively from all the benzenoid derivatives. The thermal ring opening of the primary photoadduct and the photolability of the cycloocta‐1,3,5‐triene isomer depend markedly on the position of the substituents.