title: Stereoselective Csp(3) -Csp(2) Bond-Forming Reactions by Transition-Metal-Free Reductive Coupling of Cyclic Tosylhydrazones with Boronic Acids.
abstract: The reactions between alkenylboronic acids and tosylhydrazones derived from substituted cyclohexanones lead to the construction of disubstituted cyclohexanes with total regio- and stereoselectivity. In these transition-metal-free processes, a Csp(3) -Csp(2) and Csp(3) -H bond are formed on the same carbon atom. The stereoselective reaction is general for 2-, 3-, and 4-substituted cyclohexanone tosylhydrazones, as well as for 2-substituted cyclopentanones. However, no stereoselectivity is observed for acyclic derivatives. DFT computational modeling suggests that the stereoselectivity of the reaction is determined by the approach of the boronic acid to the diazocyclohexane on its most stable chair conformation through an equatorial trajectory.
authors.affiliation: Departamento de Química Orgánica e Inorgánica and Instituto Universitario de Química Organometálica "Enrique Moles", Universidad de Oviedo, c/Julián Clavería 8, Oviedo, 33006, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Plaza
authors.affiliation: Departamento de Química Orgánica e Inorgánica and Instituto Universitario de Química Organometálica "Enrique Moles", Universidad de Oviedo, c/Julián Clavería 8, Oviedo, 33006, Spain.
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Pérez-Aguilar
authors.affiliation: Departamento de Química Orgánica e Inorgánica and Instituto Universitario de Química Organometálica "Enrique Moles", Universidad de Oviedo, c/Julián Clavería 8, Oviedo, 33006, Spain. acvg@uniovi.es.
authors.forename: Carlos
authors.initials: C
authors.lastname: Valdés
keywords: boronic acids; diazo compounds; reductive coupling; stereoselectivity; tosylhydrazones