Enantioselective organo-cascade catalysis

Journal of the American Chemical Society

Volumn 127, Issue 43, 2005, Pages 15051-15053

  Huang, Yong ^a   Walji, Abbas M ^a   Larsen, Catharine H ^a   MacMillan, David W C ^a  

^a California Institute of Technology   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ALDEHYDE; ENAMINE; IMIDAZOLIDINE DERIVATIVE; IMINE; ORGANIC COMPOUND;

ARTICLE; CATALYSIS; CATALYST; ENANTIOSELECTIVITY; PRECURSOR; REACTION ANALYSIS; SOLVENT EFFECT;

ALDEHYDES; AMINES; BIOLOGICAL PRODUCTS; CATALYSIS; IMIDAZOLES; IMINES; MODELS, CHEMICAL; ORGANIC CHEMICALS; OXIDATION-REDUCTION; STEREOISOMERISM;

EID: 27544485685     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja055545d     Document Type: Article

References (22)

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19. For selected applications in total synthesis, see: (e) Nicolaou, K. C.; Montagnon, T.; Snyder, S. A. Chem. Commun. 2003, 551.
20. General procedure: to a 2-dram vial equipped with a magnetic stir bar and charged with catalyst (0.05 mmol) were added EtOAc (0.25 mL) and TFA (0.05 mmol), and then the solution was cooled to the indicated temperature. To this solution was added the enal (0.75 mmol) followed by the nucleophile (0.25 mmol) and the electrophile (0.5 mmol). Upon consumption of starting materials, the solution was passed through Iatrobeads with Et2U, and then concentrated in vacuo. The resulting residue was purified by Iatrobead chromatography.
21. Superior yields were obtained when the electrophile was added after consumption of the Hantzsch ester (as determined by TLC or GLC).
22. For example, if two catalytic cycles, each 86% ee selective, were combined, the resulting cascade would furnish a 7:1 mixture of diastereomers, with the major diastereomer being formed in 99% ee.