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DOI: 10.1055/s-0030-1258673
Precipitation Induced Nonlinear Effects in Phosphoric Acid Catalysis
N. Li, X.-H. Chen, S.-M. Zhou, S.-W. Luo, J. Song, L. Ren, L.-Z. Gong*
University of Science and Technology of China, Hefei, Chengdu Institute of Organic Chemistry and Graduate School of Chinese Academy of Sciences, Beijing, P. R. of China
Publikationsverlauf
Publikationsdatum:
22. September 2010 (online)
Significance
A strong positive nonlinear effect (NLE) of phosphoric acid catalyst 1 is reported (see also: D. G. Blackmond and co-workers Nature 2006, 441, 621). The single crystal structures of racemic and enantiopure 1 have different patterns of hydrogen bonding networks with water, which render an energy difference between a racemate and a conglomerate. Also, a positive NLE was observed for various reactions with substrates, which do not contain a hydrogen bonding interrupting functional group. Otherwise, a NLE could not be observed with basic substrates, which can disturb hydrogen bonding and dissolve the catalyst in a non-polar solution. However, after removing precipitated phosphate 1, a NLE could be detected for the reactions with basic substrates.