Premium
Photochemistry of 2,6‐dimethyl‐4‐pyrone in trifluoroethanol
Author(s) -
Keil Elinor B.,
Pavlik James W.
Publication year - 1976
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570130550
Subject(s) - chemistry , zwitterion , photodissociation , pyrone , dimer , photochemistry , yield (engineering) , ring (chemistry) , solvent , organic chemistry , molecule , materials science , metallurgy
Photolysis of 2,6‐dimethyl‐4‐pyrone ( 1 ) in trifluoroethanol gave, in addition to the previously observed dimer 2 , three volatile primary photoproducts 3, 4 , and 5. Continued irradiation led to the disappearance of the three volatile products with formation of 6. This secondary photo‐product was shown to arise from 3 and 4 while 5 was converted to non‐volatile products. The formation of 3, 4 , and 5 can be viewed as arising from an oxybicyclohexenyl zwitterion formed by electrocyclic ring closure of 1. This zwitterion can thus be trapped by solvent to yield 3 and 4 or rearrange to 5 via and epoxycyclopentenone intermediate. The conversion of 3 and 4 to 6 is explained in terms of a Norrish type II process.