Development of Novel Chiral Synthons for 2-Amino Alcohols of Biological Interest.

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1. Vesatile Chiral Synthons : Using the 2-exo-alkoxy-apocamphanecarboxylic acid derivatives as chiral auxiliaries, 2-oxazolone was enantioselectively functionalized to the reactive intermediates (synthons) by means of methoxybromination, methoxyselenylation and [4+2]cycloaddition reactions. Stepwise and stereospecific conversions of the synthons, thus obtained with excellent diastereoselectivity, provided facile routes for the preparation of enantiomerically pure 2-amino alcohols.2. Syntheses of 2-Amino Alcohols of Biological Interest : The synthons, described as above, were effectively converted to bioactive amino-hydroxycarboxylic acids alcohols such as statine and its analogues, 3-amino-2-hydroxy-4-phenylbutanoic acid (component of bestatine), and 3-amino-2-hydroxy-5-methylhexanoic acid (component of amastatin), in optically pure forms as well as dihydrosphingosine.3. New Chiral Auxiliaries : Chiral 2-oxazolidinones featured by bicyclo [2.2.2] octane ring system (DHAOx and DMAOx) were synthesized and successfully utilized as highly efficient auxiliaries in the Diels-Alder reactions, alkylations, aldol reactions and the Michael reactoins. Both enentiomers of the 2-amino alcohols, readily obtained by ring opening of the above DHAOx and DMAOx, served as excellent and unique catalysts in enantioselective alkylations of aldehydes with dialkylzinc.4. Highly Reactive Condensing Reagents : Thiophosphoryl derivatives activated by 2-oxazolone were developed as powerful and stable condensing reagents for the synthesis of amides including peptides and beta-lactams, esters and thioesters.