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Formation of Cyclobutylidenepyrazolines by Methanolysis of 6‐(2,3,3‐Trifluorocyclobutenyl)‐4,5‐diazaspiro[2.4]hept‐4‐ene
Author(s) -
Guseva Ekaterina V.,
Volchkov Nikolay V.,
Tomilov Yury V.,
Averkiev Boris B.,
Nefedov Oleg M.
Publication year - 2003
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200390084
Subject(s) - chemistry , ene reaction , geminal , olefin fiber , medicinal chemistry , yield (engineering) , chloride , fluorine , stereochemistry , organic chemistry , catalysis , materials science , metallurgy
The reaction of 6‐(2,3,3‐trifluorocyclobutenyl)‐4,5‐diazaspiro[2.4]hept‐4‐ene with NaOMe in MeOH results in a mixture of isomeric (6 E )‐ and (6 Z )‐6‐(2‐fluoro‐3,3‐dimethoxycyclobutylidene)‐4,5‐diazaspiro[2.4]hept‐4‐ene due to the formal substitution of methoxy groups for two geminal fluorine atoms. Both of the isomers selectively add acetyl chloride at the azo‐olefin unit to give 4‐acetyl‐6‐(1‐chloro‐2‐fluoro‐3,3‐dimethoxycyclobutyl)‐4,5‐diazaspiro[2.4]hept‐4‐ene as the trans ‐isomer in greater than 95% yield. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2003)