Diastereoselective synthesis of benzazocines by Zn(OTf)2-catalyzed (4+4) cyclocondensation of multisubstituted donor–acceptor cyclopropanes with anthranils†
Abstract
A Zn(OTf)2-catalyzed (4+4) cyclocondensation of anthranils with 2-(trans-1-aroyl-2-arylcyclopropyl)malonates delivers a range of polycyclic benzazocines featuring an oxa-bridged eight-membered ring in excellent yields and with exclusive diastereoselectivity. Further synthetic manipulations of these products enable rapid access to diverse useful heterocyclic molecular scaffolds.