| abstract |
Processes for the production of compounds (IV) and (VIII) and (-)-tetrahydrolipstatin (XI), characterized by subjecting a compound (III) to diastereo-selective reduction to obtain a compound (IV), subjecting the compound (IV) to hexenylation, hydrolysis, reaction with sulfonyl halide or the like, deblocking, and catalytic reduction in this order to obtain compound (VIII), and then condensing the compound (VIII) with N-formyl-L-leucine in the presence of a carbodiimide condensing agent and a tertiary amine at a reaction temperature of less than 0°C. According to the processes, (-)-tetrahydrolipstatin useful as antiobestic and useful intermediates for the synthesis thereof can be efficiently produced at high optical purity and in relatively high yields in reduced steps. (III) (IV) (VIII) (XI) (wherein P2 is a hydroxyl-protecting group; and R is alkyl having 1 to 4 carbon atoms, benzyl, or 4-nitrobenzyl) |