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Synfacts 2010(5): 0597-0597
DOI: 10.1055/s-0029-1219747
DOI: 10.1055/s-0029-1219747
Organo- and Biocatalysis
© Georg Thieme Verlag
Stuttgart ˙ New York
Organocatalytic Enantioselective Chlorolactonization
D. C. Whitehead, R. Yousefi, A. Jaganathan, B. Borhan*
Michigan State University, East Lansing, USA
Weitere Informationen
Publikationsverlauf
Publikationsdatum:
22. April 2010 (online)
Significance
The authors report a unique organocatalytic enantioselective chlorolactonization reaction of alkenoic acid 1 using the Sharpless asymmetric dihydroxylation ligand (DHQD)2PHAL as the catalyst and 1,3-dichloro-5,5-diphenylhydantoin (3c) as chlorine source. In the presence of 10 mol% of catalyst, different 4-substituted pentenoic acids were cyclized in good yields and high enantioselectivities (er up to 95:5). Both the benzoic acid additive and CHCl3-hexane solvent system showed a beneficial effect on the stereoselectivity. The increase of the steric demand of the C5-substituent of hydantoin (3a-c) resulted in improved enantioselectivity.