134430-99-2Relevant articles and documents
Homochiral lithium amides for the asymmetric synthesis of β-amino acids
Davies, Stephen G.,Garrido, Narciso M.,Kruchinin, Dennis,Ichihara, Osamu,Kotchie, Luke J.,Price, Paul D.,Mortimer, Anne J. Price,Russell, Angela J.,Smith, Andrew D.
, p. 1793 - 1811 (2007/10/03)
Secondary homochiral lithium amides derived from α-methylbenzylamine undergo highly diastereoselective conjugate additions to a range of α,β-unsaturated esters. The corresponding β-amino acids are readily liberated by successive N-debenzylation and ester hydrolysis, furnishing (R)-β-amino butyric acid, (R)-β-amino pentanoic acid, (S)-β-leucine, (R)-β-amino octanoic acid, (S)-β-phenylalanine, (S)-β-tyrosine methyl ether, (S)-β-tyrosine hydrochloride and (S)-β-(2-methoxyphenyl)-β-amino propanoic acid in high yields and high ee. The application of this procedure to the synthesis of the natural products (R)-β-DOPA and (R)-β-lysine is demonstrated. The development of a simplified one-pot reaction protocol applicable to the multi-gram scale synthesis of homochiral β-amino esters is also delineated.
ASYMMETRIC SYNTHESIS OF R-β-AMINO BUTANOIC ACID AND S-β-TYROSINE: HOMOCHIRAL LITHIUM AMIDE EQUIVALENTS FOR MICHAEL ADDITIONS TO α,β-UNSATURATED ESTERS.
Davies, Stephen G.,Ichihara, Osamu
, p. 183 - 186 (2007/10/02)
Michael addition of the lithium amide derived from R-N-(α-methylbenzyl)benzylamine to benzyl E-crotonate is highly stereoselective (95percent d.e.) giving after debenzylation and crystallisation homochiral R-β-amino butanoic acid.A similar addition to methyl E-(p-benzyloxy)cinnamate is completely stereoselective giving after debenzylation and acid hydrolysis homochiral S-β-tyrosine as its HCl salt.
