A catalytic enantioselective conjugate addition of cyanide to enones.
The first synthetically useful catalytic enantioselective conjugate addition of cyanide to enones is described. The optimized conditions involved a Gd catalyst (5 or 10 mol %) derived from ligands 3 or 4 and a 1:1 ratio of TBSCN and 2,6-dimethylphenol. The reaction exhibited excellent to high enantioselectivity and a wide substrate scope. Moreover, the 1,4-adduct was exclusively produced over the 1,2-adduct. The complete regioselectivity was due both to stabilization of the 1,4-selective silylated polymetallic catalyst (7) using a TBS group and the ability of the asymmetric catalyst to promote retro-cyanation from the 1,2-adduct.
Tanaka
Yuta
Y
Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Kanai
Motomu
M
Shibasaki
Masakatsu
M
D000475:Alkenes / Q000737:chemistry*; D002384:Catalysis; D003486:Cyanides / Q000737:chemistry*; D005682:Gadolinium / Q000737:chemistry; D007659:Ketones / Q000737:chemistry*; D009570:Nitriles / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
D000475:Alkenes; D003486:Cyanides; D007659:Ketones; D009570:Nitriles; C430593:cyanohydrin; D005682:Gadolinium