Superelectrophilic Fe(III)–Ion Pairs as Stronger Lewis Acid Catalysts for (E)-Selective Intermolecular Carbonyl–Olefin Metathesis

• DOI: 10.1021/acs.orglett.0c00917
• Publication Date: 2020-04-03T16:03:24Z
• Authors: Haley Albright; Hannah L. Vonesh; Corinna S. Schindler
• Keywords: 01 natural sciences; 0104 chemical sciences

An intermolecular carbonyl-olefin metathesis reaction is described that relies on superelectrophilic Fe(III)-based ion pairs as stronger Lewis acid catalysts. This new catalytic system enables selective access to (E)-olefins as carbonyl-olefin metathesis products. Mechanistic investigations suggest the regioselective formation and stereospecific fragmentation of intermediate oxetanes to be the origin of this selectivity. The optimized conditions are general for a variety of aryl aldehydes and trisubstituted olefins and are demonstrated for 28 examples in up to 64% overall yield.