Asymmetric Induction at Remote Quaternary Centers of Cyclohexadienones by Rhodium-Catalyzed Conjugate Hydrosilylation.
The enantioselective desymmetrizing conjugate hydrosilylation of prochiral differently γ,γ-disubstituted cyclohexadienone derivatives 2 to furnish the corresponding cyclohexenones 4 with a remote chiral all-carbon quaternary center at the γ position is described. Chiral rhodium-bis(oxazolinyl)phenyl complexes 1 were effective catalysts for this transformation. This catalytic system was extended to the asymmetric transformation of spirocarbocyclic cyclohexadienones 5 to give the corresponding products 6 with high enantiomeric ratios.
Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Chikusa, Nagoya, 464-8603, Japan. yuki.n@apchem.nagoya-u.ac.jp.
Yuki
Y
Naganawa
Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Chikusa, Nagoya, 464-8603, Japan.
Mayu
M
Kawagishi
Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Chikusa, Nagoya, 464-8603, Japan.
Jun-Ichi
J
Ito
Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Chikusa, Nagoya, 464-8603, Japan. hnishi@apchem.nagoya-u.ac.jp.
Hisao
H
Nishiyama
asymmetric synthesis; desymmetrization; hydrosilylation; quaternary centers; rhodium