Enantioselective Direct Alkynylation of Ketones Catalyzed by Chiral CCN Pincer RhIIIComplexes.
A direct asymmetric alkynylation of ketones with new chiral CCN Rh catalysts containing N-heterocyclic carbene and oxazoline hybrid ligands is described. The catalytic reaction of fluoroalkyl-substituted ketones, ArCOCF2X (X=F, Cl, H), with aromatic and aliphatic alkynes yielded the corresponding chiral propargyl alcohols with high enantioselectivity. Control and kinetic experiments suggested a bis(alkynyl) Rh intermediate as the active species for the C-C bond-forming step.
Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Chikusa, Nagoya, 46408603, Japan.
Jun-Ichi
JI
Ito
Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Chikusa, Nagoya, 46408603, Japan.
Shino
S
Ubukata
Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Chikusa, Nagoya, 46408603, Japan.
Shun
S
Muraoka
Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Chikusa, Nagoya, 46408603, Japan.
Hisao
H
Nishiyama
alkynylation; asymmetric synthesis; ketones; pincer ligands; rhodium