<i>α-N</i>-Protected dipeptide acids: a simple and efficient synthesis via the easily accessible mixed anhydride method using free amino acids in DMSO and tetrabutylammonium hydroxide
作者:G. Verardo、A. Gorassini
DOI:10.1002/psc.2503
日期:2013.5
to find simple and efficient methods for their synthesis. For this reason, we have investigated the synthesis of α‐N‐protected dipeptide acids by reacting the easily accessible mixedanhydride of α‐N‐protected amino acids with free amino acids under different reaction conditions. The combination of TBA‐OH and DMSO has been found to be the best to overcome the low solubility of amino acids in organic
Employing the Structural Diversity of Nature: Development of Modular Dipeptide-Analogue Ligands for Ruthenium-Catalyzed Enantioselective Transfer Hydrogenation of Ketones
作者:Isidro M. Pastor、Patrik Västilä、Hans Adolfsson
DOI:10.1002/chem.200304900
日期:2003.9.5
stereocenters, it was demonstrated that the absolute configuration of the product alcohol was determined by the configuration of the amino acidpart of the ligand. Employing ligands based on L-amino acids generated S-configured products, and catalysts based on D-amino acids favored the formation of the R-configured alcohol. The combination N-Boc-L-alanine and (R)-phenylglycinol (Boc-L-Ab) or its enantiomer
An efficient synthesis of cyclic urethanes from Boc-protected amino acids through a metal triflate-catalyzed intramolecular diazocarbonyl insertion reaction
作者:Jae-Chul Jung、Mitchell A. Avery
DOI:10.1016/j.tetlet.2006.08.111
日期:2006.11
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 insertionreactions in high overall yields.
Highly Enantioselective Ruthenium-Catalyzed Reduction of Ketones Employing Readily Available Peptide Ligands
作者:Anders Bøgevig、Isidro M. Pastor、Hans Adolfsson
DOI:10.1002/chem.200305553
日期:2004.1.5
Highly efficient and selective catalysts for the asymmetric reduction of arylalkylketones under hydrogen-transfer conditions (2-propanol) were obtained by combining a novel class of pseudo-dipeptide ligands with [[RuCl(2)(p-cymene)](2)]. A library of 36 dipeptide-like ligands was prepared from N-Boc-protected alpha-amino acids and the enantiomers of 2-amino-1-phenylethanol and 1-amino-2-propanol
interesting and important to perform a nitrogen or oxygen selective reaction with interesting substrates. These atom specific reactions are crucial to specifically synthesis of specific compounds. An enantioselective N‐specific reaction of nitrosobenzene with unmodified aldehydes was successfully achieved catalyzed first by a variety of primaryamine‐based organocatalysts with higher yield and enantioselectivity