CARMONA CARMONA, JOSÉ ALBERTO, Hornillos, Valentin , Ramirez-Lopez, Pedro , Ros, Abel , Iglesias-Siguenza, Javier , Gomez-Bengoa, Enrique , Fernandez, Rosario , Lassaletta, Jose M.
Si
J. Am. Chem. Soc.
Article
Científica
14.695
05/09/2018
000444219100022
A highly diastereo- and enantioselective, scalable Pd-catalyzed dynamic kinetic asymmetric Heck reaction of heterobiaryl sulfonates with electron-rich olefins is described. The coupling of 2,3-dihydrofuran or N-boc protected 2,3-dihydropyrrole with a variety of quinoline, quinazoline, phthalazine, and picoline derivatives takes place with simultaneous installation of central and axial chirality, reaching excellent diastereo- and enantiomeric excesses when in situ formed [Pd-0/DM-BINAP] was used as the catalyst, with loadings reduced down to 2 mol % in large scale reactions. The coupling of acyclic, electron-rich alkenes can also be performed using a [Pd-0/Josiphos ligand] to obtain axially chiral heterobiaryl alpha-substituted alkenes in high yields and enantioselectivities. Products from Boc-protected 2,3-dihydropyrrole can be easily transformed into N,N ligands or appealing axially chiral, bifunctional proline-type organocatalysts. Computational studies suggest that a beta-hydride elimination is the stereocontrolling step, in agreement with the observed stereochemical outcome of the reaction.