Efficient Synthesis of β‑CF3/SCF3‑Substituted Carbonyls via Copper-Catalyzed Electrophilic Ring-Opening Cross-Coupling of Cyclopropanols

The first copper-catalyzed ring-opening electrophilic trifluoromethylation and trifluoromethylthiolation of cyclopropanols to form Csp3–CF3 and Csp3–SCF3 bonds have been realized. These transformations are efficient for the synthesis of β-CF3- and β-SCF3-substituted carbonyl compounds that are otherwise challenging to access. The reaction conditions are mild and tolerate a wide range of functional groups. Application to a concise synthesis of LY2409021, a glucagon receptor antagonist that is used in clinical trials for type 2 diabetes mellitus, is reported as well.