210548-89-3Relevant academic research and scientific papers
Asymmetric Catalytic Insertion of α-Diazo Carbonyl Compounds into O-H Bonds of Carboxylic Acids
Tan, Fei,Liu, Xiaohua,Hao, Xiaoyu,Tang, Yu,Lin, Lili,Feng, Xiaoming
, p. 6930 - 6934 (2016/10/14)
An efficient enantioselective insertion of α-diazoesters and α-diazoketones into O-H bonds of carboxylic acids was realized by the use of Rh2(OAc)4 and a chiral guanidine. Optically active α-acyloxy carbonyl compounds were generated under mild reaction conditions in high yields (up to 99%) and good enantioselectivities (up to 97.5:2.5 er).
Cu(II)-aza(bisoxazoline)-catalyzed asymmetric benzoylations
Gissibi, Anja,Finn,Reiser, Oliver
, p. 2325 - 2328 (2007/10/03)
(Chemical Equation Presented) Racemic 1,2-diols and α-hydroxy carbonyl compounds can be asymmetrically benzoylated in a kinetic resolution in the presence of various Cu(II)-aza(bisoxazoline) catalysts. A novel bisbenzyl-substituted aza(bisoxazoline) ligand proved to be especially effective when immobilized on MeOPEG5000, giving from 91 to ≥99% ee in 37-49% yield for each of five sequential reactions.
N-acylpyridinium trifluoromethanesulfonates and tetrafluoroborates: Shuttle reagents for the acylation of enantiopure secondary alcohols
Wagner, Rüdiger,Günther, Wolfgang,Anders, Ernst
, p. 883 - 888 (2007/10/03)
Several enanflopure alcohols are esterified with N-acyl-4- benzylpyfidinium trifluoromethanesulfonates 7b,d,f or tetrafluoroborates 7a,c,e. These reagents, which can be generated in situ, or isolated as stable salts, are synthesized from readily available 4-alkylpyridines 3, acyl chlorides 4 and strong protic acids 6. The acyl moiety is transferred under neutral conditions and in high yields. The heterocyclic component 3a can be re-isolated almost quantitatively. The acetate, benzoate and pivaloate groups were selected with regard to their application as frequently used protecting groups for hydroxy compounds. As shown by paramagnetic shift experiments with a chiral europium(III) complex, these acylations proceed without detectable racemization or epimerization.
