Reactions of Donor-Acceptor Cyclopropanes with Naphthoquinones: Redox and Lewis Acid Catalysis Working in Concert

Lücht, Alexander; Patalag, Lukas, J.; Augustin, André, U.; Jones, Peter, G.; Werz, Daniel, B.

doi:10.24355/dbbs.084-201802141056

Published

Reactions of Donor-Acceptor Cyclopropanes with Naphthoquinones : Redox and Lewis Acid Catalysis Working in Concert

Lücht, Alexander; Patalag, Lukas J.; Augustin, André U.; Jones, Peter G.; Werz, Daniel B.

Reactions of 2-aryl cyclopropane dicarboxylates with naphthoquinones are reported. The key feature was the use of catalytic amounts of SnCl2, which acts as both electron donor and Lewis acid. By an in-situ umpolung of naphthoquinone the formerly electrophilic species is converted into a nucleophile that is able to trigger the ring-opening of the three-membered ring with formation of a new C-C bond. Treatment of these products with base under oxidative conditions resulted - by losing methyl formate - in cyclopentannulated products with fully conjugated π systems exhibiting intensive absorptions in the visible range.