The acylation of 8-demethoxy-1-azaflavaglines by dimethylcarbamoyl chloride was found to operate with an inversion of configuration, which is rationalized by the occurrence of styrylurea intermediate. The configuration-reversed products were not observed when the substrate was substituted by a methoxy in position 8, suggesting that an overstabilization of the carbocationic intermediate prevents this reaction to take place.
Key words
inversion of configuration - amino alcohol - flavaglines