93303-74-3Relevant articles and documents
Asymmetric Epoxidation of Unfunctionalized Olefins Using Novel Chiral Dihydroisoquinolinium Salts as Organocatalysts
Ali, K. Ben
, p. 638 - 646 (2021/06/02)
Abstract: Two new non-racemic chiral dihydroisoquinolinium salts with N-substituents bulkier than a methyl group have been synthesized from (1S,2R)-norephedrine. These salts were used to catalyze asymmetric epoxidation of a series of prochiral olefins. One of the two new catalysts provided higher enantioselectivities (up to 66% ee) than the reference salt containing an N-methyl substituent.
Diastereoselective reduction of α-aminoketones: Synthesis of anti- and syn-β-aminoalcohols
Fraser, David S.,Park, Sheldon B.,Chong, J. Michael
, p. 87 - 101 (2007/10/03)
Reduction of N-t-BOC-protected-N-alkyl α-aminoketones with LiEt 3BH or Li(S-Bu)3BH furnishes protected syn-β-aminoalcohols with high selectivities. In contrast, removal of the BOC group followed by reduction of the aminoketone gives anti-β- aminoalcohols with variable selectivities. With aromatic ketones, selectivities are typically high while aliphatic ketones show mediocre to high selectivities depending on steric considerations.
(β-amino alcohol)(arene)ruthenium(II)-catalyzed asymmetric transfer hydrogenation of functionalized ketones - Scope, isolation of the catalytic intermediates, and deactivation processes
Everaere, Kathelyne,Mortreux, André,Bulliard, Michel,Brussee, Johannes,Van Der Gen, Arne,Nowogrocki, Guy,Carpentier, Jean-Fran?ois
, p. 275 - 291 (2007/10/03)
The asymmetric transfer hydrogenation of functionalized ketones with (β-amino alcohol)(arene)RuII catalysts using 2-propanol as the hydrogen source has been studied. The structure of the catalyst has been systematically screened using a wide variety of [(η6-arene)RuCl2]2 complexes and β-amino alcohols R1CH(OH)CHR2NHR3, some of which were specifically designed for optimized performance, e.g. (1S,2R)-N-(4-biphenylmethyl)norephedrine (9ο). The efficiencies of the catalytic combinations have been evaluated in the reduction of β-oxo esters and ketones bearing heteroatoms at the α-position. The catalyst precursor [{η6-p-cymene}{η2-N,O-(9ο)}RuCl] (35), the 16-electron true catalyst [{η6-p-cymene}{η2-N,O-(9ο1-) }Ru] (36), and the hydride [{η6-p-cymene}{η2-N,O-(9ο)}RuH] (37) involved in the reduction process have been isolated, characterized by NMR and ESI-MS, as well as by X-ray crystallography in the case of 35, and their reactivities have been investigated. The results reveal two general trends regarding this catalytic process: (1) the apparent reaction rate and the enantioselectivity are largely controlled by the nature of the amine functionality of the chiral ligand and the arene ring of the RuII precursor; (2) side reactions occur between the ketone substrate and the active catalytic species that affect the concentration of the latter and consequently the apparent rate; the formation of inactive (β-diketonato)RuII complexes is demonstrated in the case of β-oxo esters.
