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Unusual fragmentation of trimethylsilylated enols derived from m ‐ and p ‐hydroxyacetophenones
Author(s) -
Kraus Rupert,
Spiteller Gerhard
Publication year - 1989
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.1210241002
Subject(s) - chemistry , fragmentation (computing) , trimethylsilyl , ether , mass spectrum , enol ether , hydrogen , enol , medicinal chemistry , acetal , methyl group , stereochemistry , group (periodic table) , organic chemistry , mass spectrometry , catalysis , chromatography , computer science , operating system
When 4‐hydroxyacetophenone is treated with MSTFA the corresponding bis‐trimethylsilylated enol ether (1a) is obtained. The mass spectrum of la is characterized by a [M – 1] + base peak. Extensive deuteration experiments revealed that the hydrogen is mainly removed from a ring position, but originates also to some extent from the side chain (methylidene group) and even to a very small amount from the hydrogens of the methyl groups of the enolic trimethylsilyl group. A mechanism for this fragmentation behaviour is formulated.