Design and Synthesis of a Prototype Scaffold for Five-Residue -Helix Mimetics

The development of structural mimetics of -helices has traditionally focused on representation of the three residues that protrude from one face of the helical surface on three consecutive turns (i.e., i, i+3/i+4, and i+7). Despite the decisive contribution these residues make to the binding interaction with protein partners, peripheral residues can play important roles particularly with regard to imparting selectivity. Here, we describe the design and synthesis of a model azabicyclo[2.2.2]octane aryl amide scaffold designed to compactly present the i, i+1, i+2, i+4, and i+5 residues of an -helix.