Please use this identifier to cite or link to this item:
|Title:||Oxyanion hole stabilization by C-H·O Interaction in a transition state -a three-point interaction model for cinchona alkaloid-catalyzed asymmetric methanolysis of meso -cyclic anhydrides|
|Authors:||Yang, H. |
|Source:||Yang, H., Wong, M.W. (2013-04-17). Oxyanion hole stabilization by C-H·O Interaction in a transition state -a three-point interaction model for cinchona alkaloid-catalyzed asymmetric methanolysis of meso -cyclic anhydrides. Journal of the American Chemical Society 135 (15) : 5808-5818. ScholarBank@NUS Repository. https://doi.org/10.1021/ja4005893|
|Abstract:||Oxyanion holes are commonly found in many enzyme structures. They are crucial for the stabilization of high-energy oxyanion intermediates or transition states through hydrogen bonding. Typical functionalities found in enzyme oxyanion holes or chemically designed oxyanion-hole mimics are N-H and O-H groups. Through DFT calculations, we show that asymmetric methanolysis of meso-cyclic anhydrides (AMMA) catalyzed by a class of cinchona alkaloid catalysts involves an oxyanion hole consisting of purely C-H functionality. This C-H oxyanion hole is found to play a pivotal role for stabilizing the developing oxyanion, via C-H·O hydrogen bonds, in our newly proposed three-point interaction transition-state model for AMMA reactions, and is the key reason for the catalyst to adopt the gauche-open conformation in the transition state. Predicted enantioselectivities of three cinchona alkaloid catalysts, namely DHQD-PHN, DHQD-MEQ, and DHQD-CLB, based on calculations of our transition-state model, agree well with experimental findings. © 2013 American Chemical Society.|
|Source Title:||Journal of the American Chemical Society|
|Appears in Collections:||Staff Publications|
Show full item record
Files in This Item:
There are no files associated with this item.
checked on Feb 21, 2018
WEB OF SCIENCETM
checked on Jan 16, 2018
checked on Feb 18, 2018
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.