Asymmetric Hydrocyanation of 3-Phenoxybenzaldehyde Catalyzed by Poly(cinchona alkaloid-co-acrylonitrile)s

Abstract

Asymmetric addition of hydrogen cyanide to 3-phenoxybenzaldehyde catalyzed by poly(quinidine-co-acrylonitrile) affords (S)-2-hydroxy-2-(3′-phenoxyphenyl)acetonitrile in a moderate optical yield.

Nucleophilic Chiral Amines as Catalysts in Asymmetric Synthesis

“…The asymmetric addition of hydrogen cyanide to 3-phenoxybenzaldehyde catalyzed by a quinidine-acrylonitrile copolymer 166 was shown to give cyanohydrins in high yield (98%) with moderate selectivity (46% ee) (eq 38) . The selectivities achieved were substantially higher than those from the monomeric alkaloid (22% ee).…”

Facile Synthesis of Polymer-Supported Cinchona Alkaloid Catalysts for Asymmetric Michael Reaction

“…3 Copolymerizations of a vinyl group at C-3 in cinchona alkaloids with vinyl monomers such as acrylonitrile or methacrylates were reported to be difficult. [4][5][6][7][8][9][10][11] But the double bond has no homopolymerizability and low copolymerizability with other vinyl monomers. The authors expect that the introduction of mathacrylate units into cinchona alkaloids would be useful for increasing polymerizability and controlling cooperative interactions between cinchona alkaloids as chiral ligand units and polymer matrix.…”

Asymmetric Synthesis of Cyanohydrins

“…Thus, Lipton added (S)-mandelonirtile at the start of the reaction to enhance the enantioselectivity from 53% to 81% ee. (1) Additionally, alternative procedures using chiral polymers, or supported organocatalysts, have been developed to produce cyanohydrins with up to 98% ee [65][66][67][68][69]. Later many structural modifications (6-9) have been made towards higher catalytic efficiency for aliphatic and aromatic aldehydes, keeping the (S)-histidine residue unchanged in all cases as shown in Fig.…”