Two independent routes to the formal synthesis of (–)-epiquinamide, have been described: the first route utilizes an
l
-proline-catalyzed one-pot sequential α-amination/propargylation of aldehyde, while the second one employs asymmetric dihydroxylation as the key reaction to install the stereochemistry. While the first synthesis was accomplished in nine steps with 24.4% overall yield and dr 9:1, the second strategy resulted in the synthesis in eight steps with 36.4% overall yield and with perfect enantiocontrol.
Key words
amination - dihydroxylation - diastereoselective - proline - quinolizidine