title: Regiocontrolled Cu(I)-catalyzed borylation of propargylic-functionalized internal alkynes.
abstract: Good to excellent reactivity and regiocontrol have been achieved in the Cu(I)-catalyzed borylation of dialkyl internal alkynes with bis(pinacolato)diboron. The presence of a propargylic polar group (OH, OR, SAr, SO(2)Ar, or NHTs), in combination with PCy(3) as ligand, allowed maximizing the reactivity and site-selectivity (β to the propargylic function). DFT calculations suggest a subtle orbitalic influence from the propargylic group, matched with ligand and substrate size effects, as key factors involved in the high β-selectivity. The vinylboronates allowed the stereoselective synthesis of trisubstituted olefins, while allylic substitution of the SO(2)Py group without affecting the boronate group provided access to formal hydroboration products of unbiased dialkylalkynes.
authors.affiliation: Departamento de Química Orgánica, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain.
authors.forename: Abraham L
authors.initials: AL
authors.lastname: Moure
authors.forename: Ramón
authors.initials: R
authors.lastname: Gómez Arrayás
authors.forename: Diego J
authors.initials: DJ
authors.lastname: Cárdenas
authors.forename: Inés
authors.initials: I
authors.lastname: Alonso
authors.forename: Juan C
authors.initials: JC
authors.lastname: Carretero