New multicomponent domino reactions (MDRs) in water: highly chemo-, regio- and stereoselective synthesis of spiro{[1,3]dioxanopyridine}-4,6-diones and pyrazolo[3,4-b]pyridines
2010; Royal Society of Chemistry; Volume: 12; Issue: 8 Linguagem: Inglês
10.1039/c0gc00073f
ISSN1463-9270
AutoresNing Ma, Bo Jiang, Ge Zhang, Shu‐Jiang Tu, Walter J. Wever, Guigen Li,
Tópico(s)Synthesis and Characterization of Heterocyclic Compounds
ResumoNew multicomponent domino reactions (MDRs) have been established for the synthesis of spiro{pyrazolo[1,3]dioxanopyridine}-4,6-diones, spiro{isoxazolo[1,3]dioxanopyridine}-4,6-diones and pyrazolo[3,4-b]pyridines. The MDRs were conducted by reacting readily available and inexpensive starting materials in aqueous solution under microwave irradiation. A total of 26 examples were examined, and showed a broad substrate scope and high overall yields (76–93%). A new mechanism has been proposed to explain the reaction process and the resulting chemo-, regio- and stereoselectivity. The present green synthesis shows attractive characteristics such as the use of water as the reaction medium, one-pot conditions, short reaction periods (9–13 min), easy work-up/purification and reduced waste production without the use of any acids or metal promoters.
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