74879-45-1Relevant academic research and scientific papers
Route to Quaternary Oxaprolinol Derivatives as Masked Precursors of Disubstituted β3,β3-Amino Aldehyde
Shpak-Kraievskyi, Pavlo,Mankou Makaya, Amelle,Beauchard, Anne,Martel, Arnaud,Laurent, Mathieu Y.,Dujardin, Gilles
, p. 3923 - 3934 (2015)
Bicyclic isoxazolidines displaying one or two quaternary stereocenter(s) were formed starting from functional cyclic ketonitrones equipped with a phenyl glycinol chiral auxiliary. The products were engaged in stereocontrolled 1,3-dipolar cycloaddition reactions with a range of electron-rich and electron-poor dipolarophiles. A new reductive removal of the phenyl glycinol chiral auxiliary was introduced and was shown to afford chemoselectively a quaternary isoxazolidine derivative (of oxaprolinol-type) without cleaving the N-O isoxazolidine bond. Keeping the aldehyde function masked as a cyclic pseudo-acetal, the liberated oxy-amine function was shown to be available for a pseudo-peptide coupling with various N-protected amino acids. The isoxazolidine ring was opened by a reductive N-O bond cleavage, giving a pseudo-dipeptide that was C-terminated with an aldehyde function. Isoxazolidines displaying a quaternary stereocenter were formed starting from functional cyclic ketonitrones through a highly stereocontrolled 1,3-dipolar cycloaddition. Chemoselective reductive chiral auxiliary removal gives quaternary oxaprolinol derivatives, which were further transformed into dipeptides terminated directly with an aldehyde function.
Substituent effects in ring-chain tautomerism of the condensation products of non-racemic 1,2-aminoalcohols with aromatic aldehydes
Juhasz, Marta,Lazar, Laszlo,Fueloep, Ferenc
experimental part, p. 2012 - 2017 (2012/03/22)
The condensation of (S)-2-amino-2-phenylethanol or (S)-2-amino-3- phenylpropanol with substituted benzaldehydes in methanol or water led to crystalline products, which proved to exist in CDCl3 at 300 K as three-component (ringcis-ope
A novel one-pot procedure for the stereoselective synthesis of α-hydroxy esters from ortho esters
Breunlng, Matthias,Haeuser, Tobte,Tanzer, Eva-Maria
supporting information; experimental part, p. 4032 - 4035 (2009/12/09)
A novel one-pot procedure for the stereoselective synthesis of a-hydroxy esters from ortho esters was developed. Key steps were multiheteroatom Cope rearrangements of O-acylated N-hydroxy-L-tert-leucinol-derived oxazoline N-oxides leading to a-acyloxy oxazolines and, after methanolysis, to the target molecules in 67-80% yield and 94-98% ee.
