Asymmetric Allylic C–H Oxidation for the Synthesis of Chromans
journal contributionposted on 2015-10-14, 00:00 authored by Pu-Sheng Wang, Peng Liu, Yu-Jia Zhai, Hua-Chen Lin, Zhi-Yong Han, Liu-Zhu Gong
An enantioselective intramolecular allylic C–H oxidation to generate optically active chromans has been accomplished under the cooperative catalysis of a palladium complex of chiral phosphoramidite ligand and 2-fluorobenzoic acid. Mechanistic studies suggest that this reaction commences with a Pd-catalyzed allylic C–H activation event and then undergoes asymmetric allylic alkoxylation. The synthetic significance of the method has been embodied by concisely building up a key chiral intermediate to access (+)-diversonol.