Catalytic Site-Selective Acylation of Carbohydrates Directed by Cation-n Interaction
Guozhi Xiao1, Gabriel A Cintron-Rosado2, Daniel A Glazier1,3
1School of Pharmacy, University of Wisconsin-Madison , Madison, Wisconsin 53705, United States.
Abstract:
Site-selective functionalization of hydroxyl groups in carbohydrates is one of the long-standing challenges in chemistry. Using a pair of chiral catalysts, we now can differentiate the most prevalent trans-1,2-diols in pyranoses systematically and predictably. Density functional theory (DFT) calculations indicate that the key determining factor for the selectivity is the presence or absence of a cation-n interaction between the cation in the acylated catalyst and an appropriate lone pair in the substrate. DFT calculations also provided a predictive model for site-selectivity and this model is validated by various substrates.
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