Palladium-catalysed stereoselective [3 + 2] annulation of vinylethylene carbonates and tryptanthrin-based ketones

Abstract

The palladium-catalysed [3 + 2] annulation of vinylethylene carbonates (VECs) and ketones remains challenging in organic synthesis. Herein, we successfully achieved the [3 + 2] annulation of tryptanthrin-based ketones and VECs for the efficient synthesis of indoloquinazolinone derivatives with generally excellent yields and good diastereoselectivity. Notably, the asymmetric version of this [3 + 2] annulation can also be achieved by using a chiral spiroketal-based diphosphine ligand. In addition, preliminary biological studies reveal that some of the products exhibit promising antibacterial activity.