title: Chemoselective Palladium-Catalyzed Deprotonative Arylation/[1,2]-Wittig Rearrangement of Pyridylmethyl Ethers.
abstract: Control of chemoselectivity is one of the most challenging problems facing chemists and is particularly important in the synthesis of bioactive compounds and medications. Herein, the first highly chemoselective tandem C(sp3)-H arylation/[1,2]-Wittig rearrangement of pyridylmethyl ethers is presented. The efficient and operationally simple protocols enable generation of either arylation products or tandem arylation/[1,2]-Wittig rearrangement products with remarkable selectivity and good to excellent yields (60-99%). Choice of base, solvent, and reaction temperature play a pivotal role in tuning the reactivity of intermediates and controlling the relative rates of competing processes. The novel arylation step is catalyzed by a Pd(OAc)2/NIXANTPHOS-based system via a deprotonative cross-coupling process. The method provides rapid access to skeletally diverse aryl(pyridyl)methanol core structures, which are central components of several medications.
authors.affiliation: Department of Medicinal Plants, Agronomy College, Sichuan Agricultural University, 211, Huimin Rd, Wenjiang Region, Chengdu 611130, PR China; Roy and Diana Vagelos Laboratories, Penn/Merck Laboratory for High-Throughput Experimentation, Department of Chemistry, University of Pennsylvania, 231 S, 34 St., Philadelphia, PA 19104-6323 (USA).
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.affiliation: Roy and Diana Vagelos Laboratories, Penn/Merck Laboratory for High-Throughput Experimentation, Department of Chemistry, University of Pennsylvania, 231 S, 34 St., Philadelphia, PA 19104-6323 (USA).
authors.forename: Byeong-Seon
authors.initials: BS
authors.lastname: Kim
authors.affiliation: Roy and Diana Vagelos Laboratories, Penn/Merck Laboratory for High-Throughput Experimentation, Department of Chemistry, University of Pennsylvania, 231 S, 34 St., Philadelphia, PA 19104-6323 (USA).
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Walsh