115549-25-2Relevant articles and documents
An efficient synthesis of cyclic urethanes from Boc-protected amino acids through a metal triflate-catalyzed intramolecular diazocarbonyl insertion reaction
Jung, Jae-Chul,Avery, Mitchell A.
, p. 7969 - 7972 (2006)
A simple and efficient synthesis of cyclic urethanes and related oxazinanones 1a-l from diazoketones 3a-l is described. The transformation involves generation of carbenes by activation of diazo groups using metal triflates in intramolecular diazocarbonyl insertion reactions in high overall yields.
On the Preparation of β-Amino Acids from α-Amino Acids Using the Arndt-Eistert Reaction: Scope, Limitations and Stereoselectivity. Application to Carbohydrate Peptidation. Stereoselective α-Alkylations of Some β-Amino Acids
Podlech, Joachim,Seebach, Dieter
, p. 1217 - 1228 (2007/10/02)
The Arndt-Eistert homologation of α-amino acids was studied to determine the stereoselectivity in this reaction by chromatographic up-to-date analytical methods.While carbamate-protected phenylglycine was transformed to the corresponding β-amino acid methyl ester with a stereoselectivity of only 9:1, all other tested amino acid derivatives (Ala, Phe, Ser, Orn, tert-Leu and perhydro-azepine-2-carboxylic acid, suitably protected) were homologated with full retention of configuration (products 9-17).The intermediate diazo ketones 1-8 were purified and characterized by their NMR spectra.When nucleophiles derived from partially protected sugars were present during decomposition of the diazo ketones (derived from amino acids or dipeptides), a strong dependence of the yield (products 21-24) on the degree of steric hindrance of the nucleophilic OH group was observed.Two of the β-amino acids obtained from the homologation reaction were transformed to α-substituted (25-27, 31, 32) and α,α-disubstituted β-amino acid derivatives (28, 29) with excellent selctivities (in most cases, a single diastereoisomer was obtained). - Key Words: β-Amino acids, α-branched/Glycopeptides
