Contrast Performance in Catalytic Ability — New Cinchona Phase Transfer Catalysts for Asymmetric Synthesis of α‐Amino Acids.

Abstract

Synthesis of α-Amino Acids. -The disappointing results obtained with title compound (Ia) are explained by a rigid transition state formed through hydrogen bonding and π-stacking in which the substrate is completely shielded by picene and cinchonidine moieties. -(ELANGO*, S.; VENUGOPAL, M.; SURESH, P. S.; ENI; Tetrahedron 61 (2005) 6, 1443-1447; Inst. Chem. Eng. Sci., Jurong Island 627833, Singapore; Eng.) -Nuesgen 23-036

Palladium catalysed asymmetric alkylation of benzophenone Schiff base glycine esters in ionic liquids

“…7,8 A third generation of chiral PTC catalysts has also been reported independently by Corey and Lygo groups. 9,10 In these reactions a variety of alkyl halides were used and either enantiomer of the product could be prepared by selective use of the pseudoenantiomeric cinchonidine 11,12 or cinchonine 13,14 derived catalysts. Further modifications of the catalytic system include dimeric, 15 trimeric 16 and other stereogenic centers 17,18 which allow many options for improving greater reactivity and selectivity.…”