Inverse electron demand Diels-Alder reactions of ethoxyethene with heterocyclic aldehydes afforded a mixture of cycloadducts and vinyl compounds resulting from a competing [2+2] pathway.
Organocatalytic asymmetric synthesis of dihydrocarbazoles via a formal [4+2] cycloaddition of in situ generated o-quinodimethanes with enals
作者:Bo-Qi Gu、Hao Zhang、Ruo-Heng Su、Wei-Ping Deng
DOI:10.1016/j.tet.2016.08.077
日期:2016.10
An organocatalytic asymmetric [4+2] eliminative cycloaddition reaction of 2-methyl-indolyl methylenemalononitriles with α,β-unsaturated aldehydes via in situ generated indole-ortho-quinodimethane intermediates has been developed. This approach provides straightforward access to 2,9-dihydro-1H-carbazole-3-carbaldehydes, as well as its analogous dihydrodibenzofuran and dihydrodibenzothiophene in good