of potential Lewisacids that has received negligible attention as a catalyst is the carbocation. Here we show the potential of triarylmethylium ions as highly powerful Lewisacidcatalysts for organic reactions. The Lewis acidity of the triarylmethylium ion can be easily tuned by variation of the electronic properties of the aromatic rings and the catalytic activity of the carbocation is shown to correlate
Iodine-catalyzed efficient conjugate addition of pyrroles to α,β-unsaturated ketones
作者:Biswanath Das、Nikhil Chowdhury、Kongara Damodar
DOI:10.1016/j.tetlet.2007.02.094
日期:2007.4
Iodine was used as a catalyst for the conjugateaddition of pyrroles to α,β-unsaturated ketones at room temperature. Mono- and dialkylated products were obtained by using equimolar amounts of the reactants. However, the use of excess enones afforded only dialkylated products.