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Computational Characterization of the Origin of Selectivity in Cycloaddition Reactions Catalyzed by Phosphoric Acid Derivatives
Author(s) -
Liu Chunhui,
Besora Maria,
Maseras Feliu
Publication year - 2016
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201501099
Subject(s) - cycloaddition , phosphoric acid , catalysis , characterization (materials science) , selectivity , chemistry , combinatorial chemistry , organic chemistry , materials science , nanotechnology
Abstract The mechanism of the organocatalyzed [4+2] cycloaddition of ο ‐hydroxybenzaldimines to 2,3‐dihydro‐2 H‐furan (DHF) to form furanobenzopyrans has been investigated by using computational methods. Experiments have shown that this reaction produces different products ( trans ‐fused or cis ‐fused) if different phosphoric acid derivatives are applied. Our study shows the reaction proceeds through a mechanism in which the imine re‐arranges into an amine, which subsequently reacts with DHF with mediation from the catalyst. The rate‐limiting step in this process is the formation of two new bonds, which is also the key step in determining the reaction selectivity. The selectivity is controlled by a balance of noncovalent interactions between the catalyst and the substrates. The discriminating factor between the two catalysts is the presence of a triflyl substituent on one of catalysts, which constraints the relative orientations of the substrates.