Abstract
© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. 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.
Original language | English |
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Pages (from-to) | 411-416 |
Journal | Chemistry - An Asian Journal |
Volume | 11 |
Issue number | 3 |
DOIs | |
Publication status | Published - 4 Feb 2016 |
Keywords
- computational chemistry
- cycloaddition
- density functional theory
- organocatalysis
- phosphoric acid esters