Stereoselective cycloaddition of N-acyliminium cations with α,β-unsaturated ketones and esters

The cycloaddition of N-acyliminium cations with some deactivated alkenes such as α,β-unsaturate ketones and esters has been investigated. In most cases, the N-acyliminium cations produced from 3-hydroxy-2-arylisoindol-1-ones in the presence of BF3·OEt2 could be reacted with α,β-unsaturated ketones and esters to afford stereoselectively the cycloaddition products 6-acylisoindolo[2,1-a]quinolin-11-ones in moderate to high yields.