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Photo Diels‐Alder Additons, V 1 1,4‐Photoadditions of α‐Morpholinoacrylonitrile to 1‐Acylnaphthalenes
Author(s) -
Döpp Dietrich,
Memarian Hamid Reza
Publication year - 1990
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19901230216
Subject(s) - chemistry , diastereomer , adduct , stereoselectivity , excited state , excitation , yield (engineering) , stereochemistry , photochemistry , organic chemistry , catalysis , physics , materials science , electrical engineering , metallurgy , engineering , nuclear physics
Photoexcited 1‐naphthaldehyde ( 1a ), 1‐acetonaphthone ( 1b ), and 1‐naphthophenone ( 1c ) add α‐morpholinoacrylonitrile ( 2a ) in a [4 + 2] mode with exceptional regio‐ and stereoselective formation of only one diastereomer of the two possible regioisomeric 1,4‐dihydro‐1,4‐ethanonaphthalene adducts. An independently formed 1,2‐adduct 4 was detected and isolated in very low yield, 4 is thermally and photochemically (313‐nm, excitation) cleaved into the starting materials with no indication of direct interconversion into 3b . Compound 3b is stable towards 313‐nm radiation, but is efficiently isomerized to give the dihydrobenzosemibullvalene 7 upon 254‐nm excitation. – All observations point to the first excited triplet state as the starting point for the 1,4‐additions.