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In a study that could help change the way chiral amino acids are synthesized in the pharmaceutical and fine chemicals industries, two groups have developed proline-catalyzed reactions for derivatizing aldehydes and ketones. The reactions use the amino acid proline as a benign organocatalyst.
The aldehyde -amination "uses readily available and inexpensive achiral starting materials and can be carried out under environmentally friendly and operationally simple reaction conditions," The aldehyde reaction allows for the practical and rapid synthesis of 2-oxazolidinones and other natural and nonnatural -amino and -hydrazino acid derivatives. Both reactions are efficient and highly selective, with yields and enantioselectivities often around 90% and sometimes exceeding 95%. "Major fine chemicals companies should be interested in the reactions because of their potential to make enantiomerically pure amino acids in a one-pot process," Such catalytic asymmetric -amination reactions have generally required the use of preformed enolates of aldehydes and ketones as substrates. The ability to use unmodified aldehydes and ketones instead of preformed enolates simplifies the process considerably.
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