Enantioselective Preparation of Ring-Fused 1-Fluorocyclopropane-1-carboxylate Derivatives: En Route to mGluR 2 Receptor Agonist MGS0028

[reaction: see text] An approach to the densely functionalized fluorocyclopropane 14, a key framework toward the synthesis of mGluR 2 receptor agonist MGS0028 (1) is reported. The Trost AAA reaction enantioselectively introduced the key allylic stereogenic center and the alpha-fluoroester moiety. Stereoselective epoxidation followed by intramolecular epoxide ring opening efficiently constructed the 1-fluorocyclopropane-1-carboxylate matrix. This route can potentially be a general methodology for a concise, highly enantio- and stereoselective synthesis of 1-fluorocyclopropane-1-carboxylate derivatives.