Transforming Natural Amino Acids into α-Alkyl-Substituted Amino Acids with the Help of the HOF·CH<sub>3</sub>CN Complex
作者:Tal Harel、Shlomo Rozen
DOI:10.1021/jo0709450
日期:2007.8.1
α-Alkyl amino acids can be efficiently prepared in high yields from the respective amino acids themselves. The key step is the oxidation of the amine function to create the corresponding α-nitro acid in a fast and very high yield reaction followed by phase-transfer alkylation and finally reduction to the desired α-alkyl amino acid. Several such acids containing aromatic rings or additional carboxylic
<b>Chelation as a Driving Force in Organic Reactions. IV.<sup>1</sup> Synthesis of α-Nitro Acids by Control of the Carboxylation-Decarboxylation Equilibrium</b><sup>2</sup>
作者:Herman L. Finkbeiner、Martin. Stiles
DOI:10.1021/ja00888a031
日期:1963.3
Concerning Selectivity in the Oxidation of Peptides by Dioxiranes. Further Insight into the Effect of Carbamate Protecting Groups
作者:Cosimo Annese、Lucia D’Accolti、Marta De Zotti、Caterina Fusco、Claudio Toniolo、Paul G. Williard、Ruggero Curci
DOI:10.1021/jo100855h
日期:2010.7.16
With use of methyl(trifluoromethyl)dioxirane (TFDO), the oxidation of some tripeptide esters protected at the N-terminus with carbamate or amide groups could be achieved efficiently under mild conditions with no loss of configuration at the chiral centers. Expanding on preliminary investigations, it is found that, while peptides protected with amide groups (PG = Ac-, Tfa-, Piv-) undergo exclusive hydroxylation at the side chain, their analogues bearing a carbamate group (PG = Cbz-, Moc-, Boc-, TcBoc-) give competitive and/or concurrent hydroxylation at the terminal N-H moiety. Valuable nitro derivatives are also formed as a result of oxidative deprotection of the carbamate group with excess dioxirane. A rationale is proposed to explain the dependence of the selectivity upon the nature of the protecting group.
New Efficient Route to .alpha.-Nitro Acids. Oxidation of Amino Acids with HOF.cntdot.CH3CN