Highly stereoselective synthesis of 1,3-aminoalcohols via Mannich reactions
摘要:
Diastereoselective synthesis of beta-amino ketones by a one-pot Mannich reaction and their subsequent reduction afforded sterically congested enantiomerically pure 1,3-aminoalcohols in high diastereoselectivity: dr up to >98:<2 over two steps. The absolute configurations of the newly created stereogenic centers were assigned by NMR spectroscopy and chemical correlation. (C) 1999 Elsevier Science Ltd. All rights reserved.
By a hydroboration/oxidation procedure ti ans-aminoalcohols with dr values from 74:26 to greater than or equal to 95:5 were obtained. A bicyclic amine derived from the unnatural amino acid 2-azabicyclic[3.3.0]octane-3-carboxylic acid was used as the chiral precursor. The absolute configuration was clarified by X-ray structure of a descendant of the tr ans-aminoalcohols. (C) 2000 Elsevier Science Ltd. All rights reserved.