Microwave-assisted solvent-free intramolecular 1,3-dipolar cycloaddition reactions leading to hexahydrochromeno[4,3-b]pyrroles: scope and limitations
摘要:
We report the microwave-assisted solvent-free synthesis of hexahydrochromeno[4,3-b]pyrroles. Intramolecular 1,3-dipolar cycloadditions proceed under these conditions within 15-40 min in 16-84% yields. An influence of the microwave irradiation upon various [3+2] cycloaddition reaction intermediates was studied. Additionally, a scope and limitations of these reactions including an influence of the dipolarophile geometry upon the cycloaddition selectivity and steric demands of the dipole upon its reactivity were also disclosed. These observations led us to postulate a preferable transition state of the reaction. Finally, an influence of the microwave irradiation to the isomerization of activated olefins was also described. (c) 2006 Elsevier Ltd. All rights reserved.
Microwave-assisted solvent-free intramolecular 1,3-dipolar cycloaddition reactions leading to hexahydrochromeno[4,3-b]pyrroles: scope and limitations
摘要:
We report the microwave-assisted solvent-free synthesis of hexahydrochromeno[4,3-b]pyrroles. Intramolecular 1,3-dipolar cycloadditions proceed under these conditions within 15-40 min in 16-84% yields. An influence of the microwave irradiation upon various [3+2] cycloaddition reaction intermediates was studied. Additionally, a scope and limitations of these reactions including an influence of the dipolarophile geometry upon the cycloaddition selectivity and steric demands of the dipole upon its reactivity were also disclosed. These observations led us to postulate a preferable transition state of the reaction. Finally, an influence of the microwave irradiation to the isomerization of activated olefins was also described. (c) 2006 Elsevier Ltd. All rights reserved.
Microwave-assisted solvent-free intramolecular 1,3-dipolar cycloaddition reactions leading to hexahydrochromeno[4,3-b]pyrroles: scope and limitations
作者:Jiří Pospíšil、Milan Potáček
DOI:10.1016/j.tet.2006.10.074
日期:2007.1
We report the microwave-assisted solvent-free synthesis of hexahydrochromeno[4,3-b]pyrroles. Intramolecular 1,3-dipolar cycloadditions proceed under these conditions within 15-40 min in 16-84% yields. An influence of the microwave irradiation upon various [3+2] cycloaddition reaction intermediates was studied. Additionally, a scope and limitations of these reactions including an influence of the dipolarophile geometry upon the cycloaddition selectivity and steric demands of the dipole upon its reactivity were also disclosed. These observations led us to postulate a preferable transition state of the reaction. Finally, an influence of the microwave irradiation to the isomerization of activated olefins was also described. (c) 2006 Elsevier Ltd. All rights reserved.