41564-41-4Relevant articles and documents
E-Olefins through intramolecular radical relocation
Kapat, Ajoy,Sperger, Theresa,Guven, Sinem,Schoenebeck, Franziska
, p. 391 - 396 (2019)
Full control over the selectivity of carbon-carbon double-bond migrations would enable access to stereochemically defined olefins that are central to the pharmaceutical, food, fragrance, materials, and petrochemical arenas. The vast majority of double-bond migrations investigated over the past 60 years capitalize on precious-metal hydrides that are frequently associated with reversible equilibria, hydrogen scrambling, incomplete E/Z stereoselection, and/or high cost. Here, we report a fundamentally different, radical-based approach.We showcase a nonprecious, reductant-free, and atom-economical nickel (Ni)(I)-catalyzed intramolecular 1,3-hydrogen atom relocation to yield E-olefins within 3 hours at room temperature. Remote installations of E-olefins over extended distances are also demonstrated.
Concave reagents. 20. Sterically shielded m-terphenyls as selective agents in general protonations
Luening,Baumgartner,Manthey,Meynhardt
, p. 7922 - 7926 (2007/10/03)
New m-terphenyls with acidic substituants in the 2′-position have been used in general protonations leading to reagent-controlled selectivity enhancements: up to 96:4 for the γ/α-protonation of unsymmetrically substituted allyl anions, up to 97:3 for the protonation of cyclohexyl anions generating preferentially the thermodynamically less stable cis-products. In order to allow a general, reagent-controlled protonation the acidity of the protonating agent should be as low as possible.
