Int. J. Mol. Sci. 2012, 13(3), 2590-2617; doi:10.3390/ijms13032590
Article

Highly Regio- and Stereoselective Diels-Alder Cycloadditions via Two-Step and Multicomponent Reactions Promoted by Infrared Irradiation under Solvent-Free Conditions

1email, 1email, 2email, 3email, 4,* email, 3email, 1email and 1,* email
Received: 15 December 2011; in revised form: 29 January 2012 / Accepted: 13 February 2012 / Published: 24 February 2012
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: Infrared irradiation promoted the Diels-Alder cycloadditions of exo-2-oxazolidinone dienes 13 with the Knoevenagel adducts 46, as dienophiles, leading to the synthesis of new 3,5-diphenyltetrahydrobenzo[d]oxazol-2-one derivatives (7, 9, 11 and 1317), under solvent-free conditions. These cycloadditions were performed with good regio- and stereoselectivity, favoring the para-endo cycloadducts. We also evaluated the one-pot three-component reaction of active methylene compounds 20, benzaldehydes 21 and exo-2-oxazolidinone diene 2 under the same reaction conditions. A cascade Knoevenagel condensation/Diels-Alder cycloaddition reaction was observed, resulting in the final adducts 1316 in similar yields. These procedures are environmentally benign, because no solvent and no catalyst were employed in these processes. The regioselectivity of these reactions was rationalized by Frontier Molecular Orbital (FMO) calculations.
Keywords: Diels-Alder cycloadditions; regioselectivity; Knoevenagel; infrared irradiation
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MDPI and ACS Style

Flores-Conde, M.I.; Reyes, L.; Herrera, R.; Rios, H.; Vazquez, M.A.; Miranda, R.; Tamariz, J.; Delgado, F. Highly Regio- and Stereoselective Diels-Alder Cycloadditions via Two-Step and Multicomponent Reactions Promoted by Infrared Irradiation under Solvent-Free Conditions. Int. J. Mol. Sci. 2012, 13, 2590-2617.

AMA Style

Flores-Conde MI, Reyes L, Herrera R, Rios H, Vazquez MA, Miranda R, Tamariz J, Delgado F. Highly Regio- and Stereoselective Diels-Alder Cycloadditions via Two-Step and Multicomponent Reactions Promoted by Infrared Irradiation under Solvent-Free Conditions. International Journal of Molecular Sciences. 2012; 13(3):2590-2617.

Chicago/Turabian Style

Flores-Conde, Maria Ines; Reyes, Leonor; Herrera, Rafael; Rios, Hulme; Vazquez, Miguel A.; Miranda, Rene; Tamariz, Joaquin; Delgado, Francisco. 2012. "Highly Regio- and Stereoselective Diels-Alder Cycloadditions via Two-Step and Multicomponent Reactions Promoted by Infrared Irradiation under Solvent-Free Conditions." Int. J. Mol. Sci. 13, no. 3: 2590-2617.

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