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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 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. Author notes that in previous studies his group also developed the first proline-catalyzed asymmetric intermolecular aldol, Mannich, and Michael reactions. However, he believes the new aldehyde -amination reaction is probably the most useful of all. "I'm convinced the technology will be applied in many academic and industrial labs," he says.
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