Conjugate addition of lithium dibenzylamide to (S)-N(3)-acryloyl-4-isopropyl-5,5-dimethyloxazolidin-2-one (derived from l-valine) and alkylation of the resultant lithium beta-amino enolate provides, after deprotection, a range of (S)-2-alkyl-3-aminopropanoic acids in good yield and high ee. Alternatively, via a complementary pathway, conjugate addition of a range of secondary lithium amides to (S)-N(3)-(2'-alkylacryloyl)-4-isopropyl-5,5-dimethyloxazolidin-2-ones, diastereoselective protonation with 2-pyridone, and subsequent deprotection furnishes a range of (R)-2-alkyl- and (R)-2-aryl-3-aminopropanoic acids in good yield and high ee. Additionally, the boron-mediated aldol reaction of beta-amino N-acyl oxazolidinones is a highly diastereoselective method for the synthesis of a range of beta-amino-beta'-hydroxy N-acyl oxazolidinones.

Conjugate addition of lithium amides to (S)-N-acryloyl- or (S)-N-2'-alkylacryloyloxazolidinones and alkylation or protonation of the resulting enolates with 2-pyridone respectively provides a highly stereoselective and product complementary route to a range of (R)- and (S)-2-alkyl-3-aminopropionic acids in good yield and in high ee.

Amino acids U 0400Asymmetric Synthesis of β 2 -Amino Acids: 2-Substituted-3-aminopropanoic Acids from N-Acryloyl SuperQuat Derivatives. -Based on N-acryloyl SuperQuat compound (I), conjugate addition of lithium amides followed by stereoselective enolate functionalization allows access to (S)-2-alkyl β 2 -amino acids (to be continued). -(BEDDOW, J. E.; DAVIES*, S. G.; LING, K. B.; ROBERTS, P. M.; RUSSELL, A. J.; SMITH, A. D.; THOMSON, J. E.; Org.

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Diastereoselective syntheses O 0031Asymmetric Synthesis of 2-Alkyl-and 2-Aryl-3-aminopropionic Acids (β 2 -Amino Acids) from (S)-N-Acryloyl-5,5-dimethyloxazolidin-2-one SuperQuat Derivatives.-Conjugate addition of lithium amides (II) and (XI) to title compounds (I), (VI), (VIII), and (X) followed by alkylation or protonation of the resulting enolates with 2-pyridone respectively provides a highly stereoselective and product complementary route to a range of β 2 -amino acids derivatives, e.g. (IV), (IX), and (XIII). -(BEDDOW, J. E.; DAVIES*, S. G.; SMITH, A. D.; RUSSELL, A. J.; Chem.