Chiral amide from (1S,2R)-(+)-norephedrine alkaloid in the enantioselective addition of diethylzinc to aryl and heteroaryl aldehydes

Chiral amide from (1S, 2R)-(+)-norephedrine and furoic acid: An efficient catalyst for asymmetric Reformatsky reaction

“…Based on the coordination mode of the catalyst CL with diethylzinc 24 and also on the radical pathway proposed by Fernandez-Ibanez et al 7,8 for asymmetric Reformatsky reaction of ketones in the presence of air, we suggest a possible mechanism for the catalytic reaction (figure 1). The presence of air was found to be crucial for effective C-C bond formation.…”

“…The chiral amide was synthesised from (1S, 2R)-(+)-norephedrine and 2-furoic acid (scheme 1) as per the reported procedure with ethylchloroformate as the activating reagent. 24 Treatment of 2-furoic acid with ethyl chloroformate in the presence of triethylamine in THF gave a mixed anhydride, which was subsequently reacted with (1S, 2R)-(+)-norephedrine to give the CL in 80% yield.…”

“…In an earlier report by our group, 24 chiral amide derived from (1S, 2R)-(+)-norephedrine and 2-furoic acid was proven to catalyse the asymmetric diethylzinc addition to prochiral aldehydes yielding the product chiral secondary alcohols in good yield and excellent enantioselectivity. Herein, we demonstrate for the first time, the application of the same chiral amide ligand in the asymmetric Reformatsky reaction with diethylzinc as zinc source.…”

Hydroxyamide-Based Ligands and Their Use in the Asymmetric Catalysis of Key Organic Transformations

“…Velmathi et al developed chiral β-hydroxyamide 19 (Figure ), synthesized from (1 S ,2 R )-(+)-norephedrine and furoic acid, and applied it to catalyze the enantioselective ethylation of aromatic and heteroaromatic aldehydes to secondary alcohols.…”

A systematic study of chiral homoprolinols and their derivatives in the catalysis of enantioselective addition of diethylzinc to aldehydes

“…As an important approach to synthesize useful and optically active secondary alcohols, the asymmetric alkylation of carbonyl compounds with organozinc reagents has been of great interest 1, 2. Since the first report by Oguni to use ( S )‐leucinol as chiral ligand in the addition of diethylzinc to benzadehyde with moderate enantiomeric excess,3 and Noyori's work with (‐)‐3‐exo‐(dimethylamino)isoborneol (DAIB) as chiral ligand,4–9 tremendous efforts have been focused on exploring new amino alcohols as efficient catalysts and diverse ligand structures have been developed to date 10–68. Among them, β‐amino alcohols have been studied extensively and proven to be the best ligands 10–23.…”