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Friday, June 29, 2012

Phosphinates


Phosphinates
  • The reaction of h-phosphinates and secondary phosphine oxides with amines and alcohols proceeds highly stereo specifically to give the corresponding coupling products with inversion of configuration at the phosphorus center under the atherton-todd reaction conditions.
  •  This finding leads to the establishment of a general and efficient method for the synthesis of a variety of optically active organo phosphorus acid derivatives from the easily available chiral h-phosphinates and secondary phosphine oxides.
  • Racemic acyl phosphinates and formyl phosphinate hydrate were used directly as the substrates in a proline derivative catalyzed cross aldol reaction with ketones.
  •  Because of the preexisting the phosphorus stereogenic center, a mixture of two diastereomers of the     corresponding a-hydroxy phosphinates were obtained in this reaction.
  •  Good to high enantioselectivities (up to 99% ee) were obtained simultaneously for both of these two diastereomers in good yields.
  •  Good diastereoselectivities were also obtained when the reaction  generates an additional carbon stereogenic centera-Hydroxyphosphinic acid
Phosphinates

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