engleski

A simple enantioselective route toward (R)- and (S)-Rolipram via anhydride desymmetrization

A highly enantioselective metal-free synthesis of both enantiomers of Rolipram is reported. The key stereoinductive step is a cinchona alkaloid catalyzed opening of a cyclic anhydride prepared from isovanillin, where both enantiomers are available using the same chiral catalyst in two protocols. An extended onepot Curtius sequence provides the lactam directly from the desymmetrization product after enrichment in high yield and excellent ee.

alkaloids; anhydrides; asymmetric catalysis

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