Synthesis of 4-aryl-6-methyl-7a-(trifluoromethyl)-2,4a,5,6,7,7a-hexahydropyrano[2,3-c]pyrrol-2-ones from 4-aryl-6-(trifluoromethyl)-2-pyrones, sarcosine, and formaldehyde
作者:Sergey A. Usachev、Natal’ya V. Popova、Vladimir S. Moshkin、Vyacheslav Ya. Sosnovskikh
DOI:10.1007/s10593-015-1795-1
日期:2015.10
4-Aryl-6-(trifluoromethyl)-2-pyrones reacted with the nonstabilized azomethine ylide obtained from sarcosine and formaldehyde under reflux in benzene for 6 h, resulting in [3+2] cycloaddition that gave 4-aryl-6-methyl-7a-(trifluoromethyl)-2,4a, 5,6,7,7a-hexahydropyrano-[2,3-c]pyrrol-2-ones in 42-56% yields. In the case of 4-aryl-3-carbethoxy-6-(trifluoromethyl)-2-pyrones, besides the respective pyrano[ 2,3-c]pyrrolidines (66-71% yields) also 4-aryl-1-methyl-2-(trifluoromethyl)pyrroles were isolated as minor products.