ASYMMETRIC SYNTHESIS OF NON-PROTEIN AMINO ACIDS

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Our ultimate goal is to develop and establish new, efficient and reliable new methodologies for the synthesis of various non-protein amino acids and related compounds with perfect control of stereochemistry. Those methodologies are very beneficial for the investigation of the biological functions on non-protein amino acids and related compounds which cannot be obtained in sufficient quantity by isolation from natural sources. As a fundamental approach to this challenging goal, we will initiate and promote the research on the asymmetric synthesis of non-protein amino acids and related compounds by applying the "beta-Lactam Synthon Method" which has been developed in our laboratory. The proposed research has two projects. In the project (1), we will develop effective methods for the asymmetric synthesis of alpha-substituted alpha-amino acids and their dipeptides on the basis of highly stereoselective mono-, double-and triple alkylations of beta-lactam esters. A new cleavage methods via 4-hydroxymethyl-beta- lactams will be examined, and new ketenes and enolates with recyclable chiral auxiliaries will be developed. In the Project (2), we will explore new and efficient routes to a variety of non-protein amino acids and their derivatives through highly stereoselective functionalizations and transformations of enantiomerically pure 3-amino-4-alkenyl-beta-lactams. We will develop various new asymmetric organic transformations during the course of this project. Those non-protein amino acids and their derivatives, thus obtained, will furnish components of naturally occurring antibiotics and their analogues, plant metabolites, enzyme inhibitors, carbohydrates, and useful building blocks of peptide hormone analogues and chiral macrocycles. We will apply the new version of "beta-Lactam Synthon Method" to the asymmetric synthesis of (i) the ceramide of gangliosides which are important glycoshingolipids associated with membranes in the brain and vertebrate cells, and (ii) (R,S)- and (R,R)-3-chloro-4- hydroxyphenylserines which are important components of vancomycinic acid.