2-Hydroxy-3-[(S)-prolinamido]pinanes as novel bifunctional organocatalysts for asymmetric aldol reactions in aqueous media
摘要:
Novel (S)-prolinamides with stereoisomeric 2-hydroxy-3-aminopinane units have been synthesized. In the presence of (1R,2R,3S,5R)-2-hydroxy-3-[(S)-prolinamido]pinane (5 mol %) cyclic ketones reacted with (hetero-)aromatic aldehydes in aqueous media to afford chiral aldols in high yields. The reaction had moderate to high diastereo- (dr up to 91/9) and enantioselectivities (up to 83% ee). (C) 2011 Elsevier Ltd. All rights reserved.
Catalytic enantioselective borane reduction of arylketones with pinene-derived amino alcohols
摘要:
Both cis- and trans-1,2-amino alcohols 5 and their N-alkylated derivatives 6 were prepared from (-)-alpha-pinene 7 as chirality source and utilized in asymmetric borane reduction of arylketones 12 employing a one-pot multi-substrate screening. The oxazaborolidine catalysts were generated in situ from amino alcohols 5 and 6 and trimethyl borate. (C) 2008 Elsevier Ltd. All rights reserved.