188241-97-6Relevant articles and documents
Enantioselective catalytic ring opening of epoxides with carboxylic acids
Jacobsen, Eric N.,Kakiuchi, Fumitoshi,Konsler, Reed G.,Larrow, Jay F.,Tokunaga, Makoto
, p. 773 - 776 (1997)
The chiral Co(salen) complex 3 is an effective catalyst for the asymmetric ring-opening of meso epoxides with benzoic acid. Enantioselectivities of 55-93% were obtained with a range of substrates.
The Activation of Carboxylic Acids via Self-Assembly Asymmetric Organocatalysis: A Combined Experimental and Computational Investigation
Monaco, Mattia Riccardo,Fazzi, Daniele,Tsuji, Nobuya,Leutzsch, Markus,Liao, Saihu,Thiel, Walter,List, Benjamin
, p. 14740 - 14749 (2016/11/18)
The heterodimerizing self-assembly between a phosphoric acid catalyst and a carboxylic acid has recently been established as a new activation mode in Br?nsted acid catalysis. In this article, we present a comprehensive mechanistic investigation on this activation principle, which eventually led to its elucidation. Detailed studies are reported, including computational investigations on the supramolecular heterodimer, kinetic studies on the catalytic cycle, and a thorough analysis of transition states by DFT calculations for the rationalization of the catalyst structure-selectivity relationship. On the basis of these investigations, we developed a kinetic resolution of racemic epoxides, which proceeds with high selectivity (up to s = 93), giving the unreacted epoxides and the corresponding protected 1,2-diols in high enantiopurity. Moreover, this approach could be advanced to an unprecedented stereodivergent resolution of racemic α-chiral carboxylic acids, thus providing access to a variety of enantiopure nonsteroidal anti-inflammatory drugs and to α-amino acid derivatives.
Organocatalytic asymmetric hydrolysis of epoxides
Monaco, Mattia Riccardo,Prevost, Sebastien,List, Benjamin
, p. 8142 - 8145 (2014/08/18)
The hydrolytic ring opening of epoxides is an important biosynthetic transformation and is also applied industrially. We report the first organocatalytic variant of this reaction, exploiting our recently discovered activation of carboxylic acids with chiral phosphoric acids via heterodimerization. The methodology mimics the enzymatic mechanism, which involves an enzyme-bound carboxylate nucleophile. A newly designed phosphoric acid catalyst displays high stereocontrol in the desymmetrization of meso-epoxides. The methodology shows wide generality with cyclic, acylic, aromatic, and aliphatic substrates. We also apply our method in the first highly enantioselective anti-dihydroxylation of simple olefins.
