Stereoselective Synthesis of Dehydroamino Acids and Its Application to the Synthesis of Nitrogen-containing Natural Products

Dehydroamino acids are often found in nitrogen-containing natural products and widely utilized as a useful intermediate for the synthesis of nitrogen-containing organic molecules. In this article, we would like to report our recent efforts toward development of the stereoselective syntheses of alpha, beta-dehydroamino acids and its application to the synthesis of nitrogen containing natural products and biologically active molecules. We developed a new olefination reagent, (diphenylpho sphono)glycine esters, which allowed smooth condensation with aldehydes to provide Edehydroamino acids in a stereoselective manner. The new method was successfully applied to the stereoselective synthesis of dehydroisoleucine and the tripeptide side chain of phomopsin A. Stereo-selective synthesis of (2S,6R)-diamino(-5R,7)-dihydroxy - heptanoic acid, 2,6 - diaminosuberic acid, and kaitocephalin via hydrogenation of dehydroamino acid moieties are also described.