ISSN:
0947-6539
Keywords:
enzyme inhibitors
;
niobium complexes
;
peptide aldehydes
;
pinacol coupling
;
vanadium complexes
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Peptide aldehydes 15 a-c are prepared without epimerization from enantiomerically pure (S)-α-amino acids (Scheme 3). Reductive pinacol homocoupling of 15 a-c, induced by vanadium complex 11 or niobium complex 16 in refluxing THF, yields C2-symmetrical (S,R,R,S)-configurated 6a, 6b and 2, respectively, with moderate to high stereoselectivity (Scheme 4). In a novel protocol for the preparation and utilization of THF solutions of 11, the isolation of air-sensitive intermediates can be avoided and the potent HIV protease inhibitor 2 prepared in enantio- and diastereomerically pure form on a kilogram scale without chromatographic purification. The (S,R,R,S) selectivity of the pinacol homocouplings is confirmed by means of an independent, stereochemically unequivocal synthesis of 6 a and 2 from D-mannitol 4 (Scheme 1).
Additional Material:
1 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/chem.19960020312
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