Localization of double and triple bonds in linear conjugated enyne-acetates and alcohols

✍ Scribed by J. Einhorn; H. Virelizier; A. Guerrero; J. C. Tabet

• Book ID: 102774891
• Publisher: John Wiley and Sons
• Year: 1985
• Tongue: English
• Weight: 599 KB
• Volume: 12
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/bms.1200120504

✦ Synopsis

Localization of double and triple bonds in linear conjugated enyne-acetates and alcohols can be achieved in microgram scale through a two-step reaction sequence: epoxidation followed by catalytic hydrogenation or deuteration. This derivatization yields a saturated secondary alcohol of RCHOH(CH2),0R'type (R = CH3(CH2),, R' = H, COCH3), by regiospecific ring opening reaction of the intermediate epoxide. The position of the hydroxyl group is clearly defined by the [M-R]+ and subsequent ions observed in the electron impact (EI) mass spectrum. The unequivocal location of the conjugated enyne system can be effected by comparing the pattern and position of the IM -Rl+ ion@) found under hydrogenation and deuteration conditions, since the same secondary alcohol may proceed from two isomeric enyne structures, i.e. CH3(CH2),CH=CH-C-C-(CH2),-30R' (enyne A) and CH3(CH,),-3C~C-CH=CH(CH,),0R' (enyne B). Metastable (mass-analysed ion kinetic energy (MIKE), HV scan) mass spectra and gas phase labelling were used for filiation attribution and mechanisms.