Optimizing the Structure of 4-Dialkylamino-α,α-diarylprolinol Ethers as Catalysts for the Enantioselective Cyclopropanation of α,β-Unsaturated Aldehydes in Water
作者:Jose I. Martínez、Efraim Reyes、Uxue Uria、Luisa Carrillo、Jose L. Vicario
DOI:10.1002/cctc.201300097
日期:2013.8
water as the reaction solvent. Moreover, the reaction was studied by computational methods, which indicated that the overall transformation proceeded through a cascadeMichael/α‐alkylation sequence, in which the first iminium‐mediated Michaeladdition reaction was the rate‐determining step and also the step at which stereochemical information was transferred from the catalyst to the products.
This work reports a one-pot asymmetric synthesis of spirocyclopropyl propionaldehydes/propanols via β,γ-bifunctionalization of propanols through the synergistic effect of a secondary amine catalyst and an oxidant.
Biocatalytic Asymmetric Cyclopropanations via Enzyme‐Bound Iminium Ion Intermediates
作者:Andreas Kunzendorf、Guangcai Xu、Mohammad Saifuddin、Thangavelu Saravanan、Gerrit J. Poelarends
DOI:10.1002/anie.202110719
日期:2021.11.2
Engineering of a promiscuous 4-oxalocrotonate tautomerase (4-OT) resulted in an unusual cofactor-independent cyclopropanationenzyme that promotes the stereoselective addition of diethyl 2-chloromalonate to substituted cinnamaldehydes to afford various cyclopropanes with high diastereo- and enantiopurity.