re- and si-Face-Selective Nitroaldol Reactions Catalyzed by a Rigid Chiral Quaternary Ammonium Salt: A Highly Stereoselective Synthesis of the HIV Protease Inhibitor Amprenavir (Vertex 478)

Either amprenavir (1) or its C(2) diastereomer can be synthesized in a simple way by the use of a nitroaldol reaction carried out in the presence of one or the other of the two ammonium ions 2. The 1,3-diamino-2-hydroxypropyl structural element of 1 is also found in many other peptidomimetics and HIV protease inhibitors. Described here is a new strategy for possible application to direct and stereocontrolled synthesis of such compounds.