Rapid fluorescent screening for bifunctional amine-acid catalysts: efficient syntheses of quaternary carbon-containing aldols under organocatalysis.
[reaction: see text] Direct catalytic aldol reactions of alpha,alpha-dialkylaldehyde donors and arylaldehyde acceptors have been performed using pyrrolidine-acetic acid bifunctional catalysts. This general and practical amine-acid combination was identified by screening catalysts using a new fluorescent detection system for carbon-carbon bond formation. Using 0.05 equiv of pyrrolidine and 0.25 equiv of acetic acid as catalyst, we obtained alpha,alpha-dialkylaldol product in 96% yield after 2 h at ambient temperature. Proline was a poor catalyst of this reaction.
Mase
Nobuyuki
N
The Skaggs Institute for Chemical Biology and the Departments of Chemistry and Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
Tanaka
Fujie
F
Barbas
Carlos F
CF
D000143:Acids / Q000737:chemistry; D000588:Amines / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D013050:Spectrometry, Fluorescence / Q000379:methods*
D000143:Acids; D000588:Amines; D002244:Carbon