Chiral ligand-controlled asymmetric conjugate addition of alpha-trimethylsilanylacetate to acyclic and cyclic enones.
The reaction of lithium ester enolate with enones provides a challenge for chemoselectivity, that is, discrimination between a conjugate addition and a 1,2-addition. Asymmetric conjugate addition of a lithium enolate of alpha-trimethylsilanylacetate to acyclic and cyclic alpha,beta-unsaturated ketones was mediated by an external chiral ligand to give the corresponding 1,4-adducts in good enantioselectivity of 74% and good chemoselectivity.
Iguchi
Mayu
M
Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan.
Doi
Hirohisa
H
Hata
Seiji
S
Tomioka
Kiyoshi
K
D003500:Cyclization; D007202:Indicators and Reagents; D007659:Ketones / Q000737:chemistry*; D008024:Ligands; D008094:Lithium / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D021241:Spectrometry, Mass, Electrospray Ionization; D013237:Stereoisomerism; D014297:Trimethylsilyl Compounds / Q000737:chemistry*
D007202:Indicators and Reagents; D007659:Ketones; D008024:Ligands; D014297:Trimethylsilyl Compounds; C488479:alpha-trimethylsilanylacetate; D008094:Lithium