Toward an understanding of the acceleration of Diels-Alder reactions by a pseudo-intramolecular process achieved by molecular recognition. A DFT study.
The pseudo-intramolecular Diels-Alder (DA) reaction between a 2-substituted furan (1) and a N-maleimide derivative (2) has been analyzed using DFT methods. Formation of two hydrogen bonds between the appendages on furan and maleimide derivatives favors thermodynamically the formation of a molecular complex (MC1) through an efficient molecular recognition process. The large enthalpy stabilization associated with the molecular recognition overcomes the unfavorable activation entropy associated with the bimolecular process. As a consequence, the subsequent DA reaction is clearly accelerated through a pseudo-intramolecular process.
Domingo
Luis R
LR
Departamento de Química OrgAnica, Universidad de Valencia, Dr. Moliner 50, 46100 Burjassot, Valencia, Spain. domingo@utopia.uv.es
Aurell
M José
MJ
Arnó
Manuel
M
Saez
José A
JA