TY - JOUR
T1 - Highly regio- and Stereoselective Diels-Alder Cycloadditions Via Two-Step and Multicomponent Reactions Promoted by Infrared Irradiation Under Solvent-Free Conditions
AU - Flores-Conde, Maria Ines
AU - Reyes, Leonor
AU - Herrera, Rafael
AU - Rios, Hulme
AU - Vazquez, Miguel A.
AU - Miranda, Rene
AU - Tamariz, Joaquin
AU - Delgado, Francisco
PY - 2012/3
Y1 - 2012/3
N2 - Infrared irradiation promoted the Diels-Alder cycloadditions of exo-2-oxazolidinone dienes 1-3 with the Knoevenagel adducts 4-6, as dienophiles, leading to the synthesis of new 3,5-diphenyltetrahydrobenzo[d]oxazol-2-one derivatives (7, 9, 11 and 13-17), 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 13-16 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.
AB - Infrared irradiation promoted the Diels-Alder cycloadditions of exo-2-oxazolidinone dienes 1-3 with the Knoevenagel adducts 4-6, as dienophiles, leading to the synthesis of new 3,5-diphenyltetrahydrobenzo[d]oxazol-2-one derivatives (7, 9, 11 and 13-17), 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 13-16 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.
KW - Diels-alder cycloadditions
KW - Infrared irradiation
KW - Knoevenagel
KW - Regioselectivity
UR - http://www.scopus.com/inward/record.url?scp=84858974721&partnerID=8YFLogxK
U2 - 10.3390/ijms13032590
DO - 10.3390/ijms13032590
M3 - Artículo
C2 - 22489113
SN - 1661-6596
VL - 13
SP - 2590
EP - 2617
JO - International Journal of Molecular Sciences
JF - International Journal of Molecular Sciences
IS - 3
ER -