Chiral bisphosphazides as dual basic enantioselective catalysts.
Chiral bisphosphazides complexed with lithium salts efficiently catalyze the direct enantioselective 1,4-addition of dialkyl malonates to acyclic enones. Spectroscopic studies on the stoichiometry of the bisphosphazide and lithium salt have indicated the formation of a 1:1 species as the active enantioselective catalyst. It is suggested that the catalyst generates a complex of the protonated phosphazide and the chiral nucleophile as the key intermediate. The phosphazide moiety appears to be a promising dual basic functionality for stereo- and chemoselective catalytic transformations.
Naka
Hiroshi
H
Graduate School of Pharmaceutical Sciences, Tohoku University, Aobayama, Sendai, Japan. naka@mail.pharm.tohoku.ac.jp
Kanase
Nobuhiko
N
Ueno
Masahiro
M
Kondo
Yoshinori
Y
D001386:Azides / Q000737:chemistry*; D002384:Catalysis; D008094:Lithium / Q000737:chemistry; D008314:Malonates / Q000737:chemistry; D010758:Phosphorus / Q000737:chemistry*; D013237:Stereoisomerism; D013379:Substrate Specificity
D001386:Azides; D008314:Malonates; D010758:Phosphorus; D008094:Lithium