171417-12-2Relevant articles and documents
A simple primary amine catalyst for enantioselective α-hydroxylations and α-fluorinations of branched aldehydes
Witten, Michael R.,Jacobsen, Eric N.
, p. 2772 - 2775 (2015/06/16)
A new primary amine catalyst for the asymmetric α-hydroxylation and α-fluorination of α-branched aldehydes is described. The products of the title transformations are generated in excellent yields with high enantioselectivities. Both processes can be performed within short reaction times and on gram scale. The similarity in results obtained in both reactions, combined with computational evidence, implies a common basis for stereoinduction and the possibility of a general catalytic mechanism for α-functionalizations. Promising initial results in α-amination and α-chlorination reactions support this hypothesis.
Microbiological transformations 43. Epoxide hydrolases as tools for the synthesis of enantiopure α-methylstyrene oxides: A new and efficient synthesis of (S)-ibuprofen
Cleij,Archelas,Furstoss
, p. 5029 - 5035 (2007/10/03)
Biohydrolysis of various α-methylstyrene oxide derivatives, differently substituted at the aromatic ring, was investigated using 10 epoxide hydrolases from different origins. Our results indicate that the enantioselectivity of these biohydrolyses strongly depends on the nature of the enzyme and of the substituent. Using some of these enzymes, this approach allows to prepare these epoxides in high optical purity. The potentiality to perform efficient preparative-scale resolution using such a biocatalyst was illustrated by the four-step synthesis of (S)-ibuprofen, a nonsteroidal antiinflammatory drug and household pain killer, one of the top-ten drugs sold worldwide. Using a combined chemoenzymatic strategy, we were thus able to set up a four-step enantioconvergent procedure allowing for the synthesis of this compound in optically pure form and with a 47% overall yield, including the resolution process, due to a possible recycling of the formed diol via chemical racemisation.
