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Alpha-fluoro-alpha-nitro(phenylsulfonyl)methane as a fluoromethyl pronucleophile: efficient stereoselective Michael addition to chalcones.

ABSTRACT: Highly efficient stereoselective 1,4-addition of racemic alpha-fluoro-alpha-nitro(phenylsulfonyl)methane (FNSM) as a fluoromethyl pronucleophile to alpha,beta-unsaturated ketones using a wide range of chiral organobifunctional catalysts under moderate conditions in the absence of an additional base has been achieved. A series of catalysts was screened for the enantioselective addition of FNSM to chalcones and the catalysts CN I, CD I, QN I-IV, and QD I were found to enable this reaction, successfully providing exclusive 1,4-addition products stereoselectively in high yields (conversion, diastereomeric ratio, and enantiomeric excess). Studies involving a model reaction and systematic analysis of the absolute configuration support the suggested mechanism.

SUBMITTER: Prakash GK

PROVIDER: S-EPMC2657402 | biostudies-literature | 2009 Mar

REPOSITORIES: biostudies-literature

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Alpha-fluoro-alpha-nitro(phenylsulfonyl)methane as a fluoromethyl pronucleophile: efficient stereoselective Michael addition to chalcones.

Prakash G K Surya GK Wang Fang F Stewart Timothy T Mathew Thomas T Olah George A GA

Proceedings of the National Academy of Sciences of the United States of America 20090223 11

Highly efficient stereoselective 1,4-addition of racemic alpha-fluoro-alpha-nitro(phenylsulfonyl)methane (FNSM) as a fluoromethyl pronucleophile to alpha,beta-unsaturated ketones using a wide range of chiral organobifunctional catalysts under moderate conditions in the absence of an additional base has been achieved. A series of catalysts was screened for the enantioselective addition of FNSM to chalcones and the catalysts CN I, CD I, QN I-IV, and QD I were found to enable this reaction, success ...[more]

PMID: 19237559

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