Polonovski reaction cyanide

Another example is provided by the application of the modified Polonovski reaction to A3-piperideines. Treatment of amine oxides (141) with trifluoroacetic anhydride results in the formation of iminium ion (142). These compounds can behave as useful synthetic intermediates, reacting with a number of nucleophiles such as cyanide ion (80JA1064). 

An interesting attempt to synthesize the ervafoline ring system was inspired by biogenetic considerations.136 Since the desired pandoline unit was not available, the condensation was studied between (318) (prepared by hydrolysis and decarboxylation of tabersonine, followed by Aa-methylation) and (319) (prepared by Polonovski reaction of 20-ep/-pandoline Nb-oxide, followed by trapping of the immonium ion with cyanide). The product (320) results from condensation of the... 

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