Synthesis of a tetrasubstituted tetrahydronaphthalene scaffold for α-helix mimicry via a MgBr2-catalyzed Friedel-Crafts epoxide cycloalkylation.

α-Helices are ubiquitous protein recognition elements that bind diverse biomolecular targets. The synthesis of a small molecule scaffold to present the side chains of an α-helix is described. The 1,3,5,7-tetrasubstituted 1,2,3,4-tetrahydronaphthalene scaffold, providing mimicry of the i, i+3, and i+4 positions of an α-helix, was synthesized using a novel MgBr2-catalyzed Friedel-Crafts epoxide cycloalkylation as the key step. Each position may be differentiated via O-alkylation after scaffold synthesis, generating a diversity-oriented approach to readily synthesize proteomimetics for different targets.