title: General allylic C-H alkylation with tertiary nucleophiles.
abstract: A general method for intermolecular allylic C-H alkylation of terminal olefins with tertiary nucleophiles has been accomplished employing palladium(II)/bis(sulfoxide) catalysis. Allylic C-H alkylation furnishes products in good yields (avg. 64%) with excellent regio- and stereoselectivity (>20:1 linear:branched, >20:1 E:Z). For the first time, the olefin scope encompasses unactivated aliphatic olefins as well as activated aromatic/heteroaromatic olefins and 1,4-dienes. The ease of appending allyl moieties onto complex scaffolds is leveraged to enable this mild and selective allylic C-H alkylation to rapidly diversify phenolic natural products. The tertiary nucleophile scope is broad and includes latent functionality for further elaboration (e.g., aliphatic alcohols, α,β-unsaturated esters). The opportunities to effect synthetic streamlining with such general C-H reactivity are illustrated in an allylic C-H alkylation/Diels-Alder reaction cascade: a reactive diene is generated via intermolecular allylic C-H alkylation and approximated to a dienophile contained within the tertiary nucleophile to furnish a common tricyclic core found in the class I galbulimima alkaloids.
authors.affiliation: Roger Adams Laboratory, Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois, 61801, United States.
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Howell
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Young
authors.forename: M Christina
authors.initials: MC
authors.lastname: White
mesh_terms: D000478:Alkylation; D002244:Carbon / Q000737:chemistry*; D006838:Hydrocarbons / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D066244:Proton Magnetic Resonance Spectroscopy
chemical_list: D006838:Hydrocarbons; D002244:Carbon; D006859:Hydrogen