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[4 + 2]‐Cycloaddition of Singlet Oxygen and Phenyltriazolinedione with Bicyclo[6.1.0]nona‐2,4,6‐triene and Derivatives
Author(s) -
Adam Waldemar,
Cueto Omar,
De Lucchi Ottorino
Publication year - 1982
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.19821150333
Subject(s) - chemistry , cyclooctatetraene , bicyclic molecule , cycloaddition , singlet oxygen , epoxide , reactivity (psychology) , stereochemistry , derivative (finance) , ring (chemistry) , medicinal chemistry , singlet state , oxygen , molecule , catalysis , organic chemistry , medicine , physics , alternative medicine , pathology , nuclear physics , financial economics , economics , excited state
The dienic reactivity of the bicyclononatrienes 1a ([4.3.0]‐isomer) and 1b ([6.1.0]‐isomer) and its oxa‐derivative 6 (cyclooctatetraene epoxide) as well as 1,3,5‐cyclooctatrienone ( 7 ), towards singlet oxygen ( 1 O 2 ) and phenyl‐1,2,4‐triazoline‐3,5‐dione (PTAD) as dienophiles has been investigated. Except for 1a , which affords the endoperoxide 9a in 60% yield, the remaining substrates 1b , 6 , and 7 do not react with 1 O 2 . With PTAD 1a , 1b , 6 , and 7 afford the urazoles 10a , 8b , 12c , and 11 , respectively. Unusual is the fact that the bicyclo[6.1.0]triene 1b leads only to the tricyclic urazole 8b , the first example of this type of [4 + 2]‐cycloadduct of 1b , while the oxa‐analog 6 affords only the tetracyclic urazole 12c . Moreover, 6 reacts with PTAD considerably more sluggishly than 1b .