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2‐substituted‐2,3‐dihydro‐4 H ‐pyrans: Competition between ‘retro Diels‐Alder’ fragmentation and substituent loss
Author(s) -
Morizur JP.,
Mercier J.,
Sarraf M.
Publication year - 1982
Publication title -
organic mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0030-493X
DOI - 10.1002/oms.1210170708
Subject(s) - substituent , fragmentation (computing) , chemistry , ether , cleavage (geology) , computational chemistry , photochemistry , mass spectrum , medicinal chemistry , stereochemistry , organic chemistry , ion , materials science , fracture (geology) , computer science , composite material , operating system
The mass spectra of two series of 2‐substituted‐2,3‐dihydro‐4 H ‐pyrans (six ethers and six carbonyl derivatives) showed a marked dependence upon the nature of the substituent. α‐Cleavage (substituent loss) was the only primary decomposition observed in the carbonyl series, while ‘retro Diels‐Alder’ reactions competed with α‐cleavage in the ether series. An unambiguous interpretation of this difference in behaviour, based on the consequence of charge localization and thermochemical data, is proposed.