Impact of Lewis Acids on Diels−Alder Reaction Reactivity: A Conceptual Density Functional Theory Study

Abstract

Density functional theory (DFT) and conceptual/chemical DFT studies are carried out in this work for the normal electron demand Diels-Alder reaction between isoprene and acrolein to compare chemical reactivity and regioselectivity of the reactants in the absence and presence of Lewis acid (LA) catalysts. A cyclic coplanar structure of acrolein-LA complex has been observed and the natural bond orbital analysis has been employed to interpret the interaction between acrolein and LAs. Reactivity indices from frontier molecular orbital energies are proved to be adequate and efficient to evaluate the catalytic property of LAs. Linear relationships have been discovered among the bond order, bond length, catalytic activation, and chemical reactivity for the systems concerned. The validity and applicability of maximum hardness principle, minimum polarizability principle, and minimum electrophilicity principle are examined and discussed in the prediction of the major regioselective isomer and the preferred reaction pathway for the reactions in the present study.

UV-spectroscopy, electronic structure and ozonolytic reactivity of sesquiterpenes: a theoretical study

“…Parr et al and other researchers [19,[26][27][28]37] suggested that DFT methods and reactivity indices are conceptually insightful and practically convenient to predict the chemical reactivity of molecules. It was anticipated that some reactivity indices are equally important for understanding structural changes.…”

“…These parameters allow us to measure the inherent quality of an isomer, instead of specific effects in a particular reaction environment [37].…”

Catalytic effect of molecular iodine in Diels–Alder reaction: a density functional theory study

“…Lewis acid catalysis of DA reaction has gained considerable attention from both experimental [4][5][6] and theoretical chemists [7][8][9][10][11][12][13][14][15][16]. Lewis acids not only improve the rate of DA reaction, it also helps in achieving high regio-and stereoselectivity compared to the uncatalyzed process [5,6].…”

“…Energetic results obtained in this study confirms that B3LYP/6-31G(d) method is an excellent compromise between computational cost and accuracy of results for theoretical study of DA reaction. Xia et al [14] studied the impact of AlCl 3 , BCl 3 , FeCl 3 , CoCl 2 , CuCl 2 , CuCl, and ZnCl 2 as Lewis acids in the DA reaction between isoprene and acrolein using both computational and conceptual/chemical DFT [17] based approaches. Use of conceptual DFT based reactivity indices [17,18] has helped in obtaining valuable insights into the role of Lewis acids in DA reactions [12][13][14][15][16].…”

“…Xia et al [14] studied the impact of AlCl 3 , BCl 3 , FeCl 3 , CoCl 2 , CuCl 2 , CuCl, and ZnCl 2 as Lewis acids in the DA reaction between isoprene and acrolein using both computational and conceptual/chemical DFT [17] based approaches. Use of conceptual DFT based reactivity indices [17,18] has helped in obtaining valuable insights into the role of Lewis acids in DA reactions [12][13][14][15][16]. Recently iodine is emerging as a very effective catalyst for various organic transformations [19][20][21].…”