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Mass spectrometry in structural and stereochemical problems—CLXXXVII A study of skeletal rearrangements in chromans by combined 13 C and deuterium labeling
Author(s) -
Trudell J. R.,
Woodgate S. D. Sample,
Djerassi Carl
Publication year - 1970
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.1210030607
Subject(s) - chemistry , deuterium , fragmentation (computing) , hydrogen–deuterium exchange , mass spectrometry , hydrogen , alkyl , aryl , stereochemistry , organic chemistry , chromatography , physics , quantum mechanics , computer science , operating system
Chroman (I), 2,2‐dimethylchroman (II), flavan (III) and 2,2‐diphenylchroman (IV) were labeled with 13 C or deuterium at every position of importance. The mass spectra of these labeled compounds make possible a detailed interpretation of some very complex carbon skeleton rearrangements. The combination of deuterium and 13 C‐labeling revealed that loss of CH 3 , C 2 H 5 and C 7 H 7 fragments from chroman (I), 2,2‐dimethylchroman (II) and 2,2‐diphenylchroman (IV) respectively, occurs by multiple pathways involving aryl or alkyl migrations with little hydrogen randomization prior to fragmentation. Although ejection of C 7 H 7 from flavan (III) occurs to a small extent by a route similar to those mentioned above, its [M C 7 H 7 ] fragment can also be formed by a pathway involving no phenyl migration but extensive hydrogen scrambling. The validity of the schemes proposed on the basis of the 13 C labeling data was checked by using them to predict the spectra of the deuterium labeled compounds.