742097-02-5Relevant academic research and scientific papers
Selective nucleophilic substitution using pyrazolate anions: Easy approach to modular chiral ligands with complexing pyrazole moieties
Kowalczyk,Skarzewski
, p. 1987 - 1999 (2008/09/18)
A simple method for the stereoselective synthesis of 3,5-disubstituted pyrazolyl alcohols from readily available chiral epoxides is reported. The key step of the synthesis is the ring-opening reaction, which occurs by a regio- and enantioselective nucleophilic substitution with pyrazolate anions. An analogous reaction of the pyrazolate anions gave nonracemic (pyrazolyl)oxazolines. Thus obtained modular pyrazole chiral ligands were tested in the Pd-catalyzed Tsuji-Trost and Cu-catalyzed asymmetric cyclopropanation reactions and the enantioselectivities up to 52% ee and 64% ee were attained in both model reactions, correspondingly.
An efficient synthesis of β-hydroxyethylpyrazoles from propylene and styrene oxide using Cs2CO3
Duprez, Virginie,Heumann, Andreas
, p. 5697 - 5701 (2007/10/03)
Bases such as caesium carbonate efficiently catalyze the regioselective ring opening of propylene and styrene oxide with various substituted pyrazoles.
