Investigation of the Configurational Stabilities of Chiral Isocyanoacetates in Multicomponent Reactions
摘要:
Isocyanoacetates are uniquely reactive compounds characterized by an ambivalent isocyano functional group and an enolizable alpha-carbon. It is widely believed that chiral alpha-substituted isocyanoacetates are configurationally unstable in some synthetically useful isocyanide-based multicomponent reactions. Herein, we demonstrate that chiral isocyanoacetates can be used with minimal to negligible epimerization in a variety of canonical Ugi four-component condensations as well as Joullie-Ugi three-component condensations, reactions that are particularly useful for constructing complex peptide structures in a single synthetic operation.
Formamide Synthesis through Borinic Acid Catalysed Transamidation under Mild Conditions
作者:Tharwat Mohy El Dine、David Evans、Jacques Rouden、Jérôme Blanchet
DOI:10.1002/chem.201600234
日期:2016.4.18
A highly efficient and mild transamidation of amides with amines co‐catalysed by borinic acid and acetic acid has been reported. A wide range of functionalised formamides was synthesized in excellent yields, including important chiral α‐amino acid derivatives, with minor racemisation being observed. Experiments suggested that the reaction rely on a cooperative catalysis involving an enhanced boron‐derived
A Simple and Convenient Synthesis of N-Formyl Amino Acid Esters Under Mild Conditions
作者:W. Duczek、J. Deutsch、S. Vieth、H.-J. Niclas
DOI:10.1055/s-1996-4153
日期:1996.1
A variety of amino acid ester hydrochlorides react with cyanomethyl formate at room temperature to give the N-formyl amino acid esters in good yields and without racemization.
A Facile Procedure for the Synthesis of<i>N</i>-Formyl Amino Acid Esters
作者:T. Chancellor、Charles Morton
DOI:10.1055/s-1994-25628
日期:——
A variety of amino acid ester hydrochlorides react with triethyl orthoformate (TEOF) or trimethyl orthoformate (TMOF) to give the N-formyl amino acid ester in good yield and high optical purity.
synthesized from natural amino alcohols or by reduction of formyl esters of α-amino acids and PPh2Cl. Their cationic rhodium complexes have been found to be excellent catalysts for enantioselective hydrogenation of dehydroamino acids (ee ∼ 86%, yield ∼ 100%) for example. Asymmetric reduction of ketones can also be performed with the new alkyl AMPP* modified rhodium catalyst (ee 50%).
Indium-Catalyzed N-Formylation of Amines under Solvent-Free Conditions
作者:Doo Jang、Joong-Gon Kim
DOI:10.1055/s-0029-1219784
日期:2010.5
We have developed a simple, mild method for N-formylation of a wide variety of amines in the presence of indium metal as a catalyst under solvent-free conditions. This reaction is applicable to the chemoselective N-formylation of amino groups and α-amino acid esters without epimerization.