| Research Abstract |
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.
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