Trimethysilyl enol ether

TMSCHN2) and an organoaluminium Lewis acid (Podlech 1998 Yang et al. 1998). The ring expansion of the tropinone 7 gave the trimethysilyl enol ether 8 in 94% yield (overall yield 53%), the first key step... 

Depending on the experimental conditions, reaction of (1) with f-butyldimethylsilyl trifluoromethanesulfonate leads either to the expected /3-trimethysilyl enol ether (11), or to its isomer (12) formed by a 1,3-migration of the trimethylsilyl group from the oxygen atom to the carbon atom (1 13). Reaction with f-butyldimethylchlorosilane always gives (12). Trimethylsilyl enol ether (11) is easily hydrolyzed to 2-(t-butyldimethylsilyl)-acetaldehyde (14) (eq 7). ... 

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