enzymatic enantioselectivedecarboxylative protonation (EDP), the corresponding chemocatalytic reactions of acyclic malonic acid derivatives remain challenging. Herein, we developed a biomimetic EDP of α-alkyl-α-aryl malonate monoesters using a chiral 1,2-trans-diaminocyclohexane-based N-sulfonamide as an organocatalyst. The method demonstrates excellent chemical yields, good enantioselectivity, mild reaction
Four new cyclopropane-based bisoxazolines were synthesized and applied to cobalt-catalyzed cross-coupling reactions between racemic alpha-bromo esters and aryl Grignard reagents. The reaction afforded a series of chiral alpha-arylalkanoic esters with high yields and good enantioselectivities (up to 93% yield, 92:8 er). This research focuses on the cross-coupling between racemic alpha-bromopropanoate and p-isobutylphenyl Grignard reagent's which provides ibuprofen ester efficiently. Furthermore, ibuprofen ester 7e was transformed into (S) -ibuprofen (99:1 er) via hydrolysis and recrystallization. (C) 2016 Elsevier Ltd. All rights reserved.