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(3): 2590-2617, 2012.
Article
em En
| MEDLINE
| ID: mdl-22489113
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.
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01-internacional
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MEDLINE
Assunto principal:
Reação de Cicloadição
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Raios Infravermelhos
Idioma:
En
Revista:
Int J Mol Sci
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
México
País de publicação:
Suíça