The asym. .alpha.-hydroxylation of N,N-diprotected .beta.-amino acid esters I (R1 = Ph, PhCH2, PhCH2OCH2; R2 = H), readily prepd. from the corresponding .alpha.-amino acids, proceeded smoothly at -78 and gave esters I (R2 = HO) in 89-95% yields and with high diastereoselectivity (up to 94% de). In comparison with other asym. .alpha.-hydroxylation procedures this method does not need the use of costly chiral reagents and/or chiral auxiliaries and represents the first example of a procedure affording .beta.-amino-.alpha.-hydroxy acids with full, orthogonal protection.
beta-Amino-alpha-hydroxy esters by asymmetric hydroxylation of homo-beta-amino acid esters / Caputo, Romualdo; Cecere, G.; Guaragna, Annalisa; Palumbo, Giovanni; Pedatella, Silvana. - In: EUROPEAN JOURNAL OF ORGANIC CHEMISTRY. - ISSN 1434-193X. - ELETTRONICO. - 17(2002), pp. 3050-3054. [10.1002/1099-0690(200209)2002:17]
beta-Amino-alpha-hydroxy esters by asymmetric hydroxylation of homo-beta-amino acid esters
CAPUTO, ROMUALDO;GUARAGNA, ANNALISA;PALUMBO, GIOVANNI;PEDATELLA, SILVANA
2002
Abstract
The asym. .alpha.-hydroxylation of N,N-diprotected .beta.-amino acid esters I (R1 = Ph, PhCH2, PhCH2OCH2; R2 = H), readily prepd. from the corresponding .alpha.-amino acids, proceeded smoothly at -78 and gave esters I (R2 = HO) in 89-95% yields and with high diastereoselectivity (up to 94% de). In comparison with other asym. .alpha.-hydroxylation procedures this method does not need the use of costly chiral reagents and/or chiral auxiliaries and represents the first example of a procedure affording .beta.-amino-.alpha.-hydroxy acids with full, orthogonal protection.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
