Photocycloaddition of four homologous 2-(cycloamino)propenenitriles to 1-acetonaphthone

Abstract

2-(Cycloamino)propenenitriles H 2 C=C(CN)N(CH 2 ) n (n = 4, 5, 6, 7) are added to triplet π,π*-excited 1-acetonaphthone forming 8b-acetyl-2-(cycloamino)-1,2,2a,8b-tetrahydrocyclobuta-[a]naphthalene-2-carbonitriles as well as 1-acetyl-9-(cycloamino)-1,4-dihydro-1,4-ethanonaphthalene-9-carbonitriles. Regio-and stereoselectivity of the photocycloadditions and the special role of the cyclobuta[a]naphthalene adducts in the initial stage of the photoadditions are discussed.