合成路线1

The enantioselective alkylation of the nickel complex (I) of the Schiff base derived from glycine and (S)-2-[N'-(N-benzylprolyl)amino]benzophenone with 4-bromo-1-butene (II) affords the corresponding complex (III) of (S)-2-amino-5-hexenoic acid, which is subsequently hydrolyzed to the free aminoacid (IV) under mild acidic conditions. Esterification of (IV) by means of SOCl2 in methanol leads to amino ester (V), and further protection with di-tert-butyl dicarbonate provides the N-Boc derivative (VI). Hydroboration of the double bond of (VI) with diisopinocampheylborane, followed by in situ oxidation with acetaldehyde gives rise to the diethyl boronate (VII). This is then converted to the isolable pinanediol boronate (IX) upon treatment with (+)-pinanediol (VIII). Finally, total deprotection of (IX) by refluxing with 12 M HCl furnishes the title compound.