Tetrahydroquinolines via Stereospecific [3+3]-Annulation of Donor-Acceptor Cyclopropanes with Nitrosoarenes

A stereospecific [3 + 3]-annulation of donor-acceptor cyclopropanes with nitrosoarenes under the influence of MgBr2 as a stoichiometric Lewis acid and reagent offers a novel approach to various structurally diverse C-8-brominated tetrahydroquinolines. In these cascades C-C, C-N, and C-Br bonds are formed. The reactions are easy to conduct and proceed under mild conditions, and the products can readily be further functionalized, rendering the method highly valuable.