1040384-28-8Relevant articles and documents
N-arylcarbonylpseudoprolines as tunable chiral derivatizing agents for the determination of the absolute configuration of secondary alcohols
Han, So-Yeong,Choi, Kihang
experimental part, p. 2920 - 2923 (2011/06/28)
New chiral derivatizing agents, 3-arylcarbonyl-2,2-dimethyloxazolidine-4- carboxylic acids (N-arylcarbonylpseudoprolines), were prepared through a simple, short-step synthesis. The absolute configuration of secondary alcohols can be assigned on the basis of the NMR spectroscopic chemical shift difference between diastereomeric pseudoproline esters. Preparation of more efficient agents was achieved simply by using aromatic groups with stronger anisotropic effect. New chiral derivatizing agents, N-arylcarbonylpseudoprolines, were prepared and used to determine the absolute configuration of secondary alcohols. Preparation of more efficient agents was achieved simply by using aromatic groups with stronger anisotropic effect.
Modular phosphite-oxazoline/oxazine ligand library for asymmetrie Pd-catalyzed allylic substitution reactions: scope and limitations - origin of enantioselectivity
Dieguez, Montserrat,Pamies, Oscar
experimental part, p. 3653 - 3669 (2009/04/23)
A library of phosphite-oxazoline/oxazine ligands L1-L15a-h has been synthesized and screened in the Pd-catalyzed allylic substitution reactions of several substrate types. These series of ligands can be prepared efficiently from easily accessible hydroxyl amino acid derivatives. Their modular nature enables the substituents/configurations in the oxazoline/oxazine moiety, alkyl backbone chain and in the biaryl phosphite moiety to be easily and systematically varied. By carefully selecting the ligand components, therefore, high regio- and enantioselectivities (ee values up to 99%) and good activities have been achieved in a broad range of mono- and disubstituted linear hindered and unhindered liner and cyclic substrates. The NMR studies on the Pd-π-allyl intermediates provide a deeper understanding about the effect of the ligand parameters on the origin of enantioselectivity. It also indicates that the nucleophilic attack takes place predominantly at the allylic terminal carbon atom located trans to the phosphite moiety.
