Stereoselective synthesis of tetra-substituted olefins via addition of zinc enolates to unactivated alkynes.
[reaction: see text] In the presence of a stoichiometric or catalytic amount of diethylzinc, a beta-aminocrotonamide undergoes sequential addition/isomerization reactions with 1-alkyne to produce, upon hydrolysis, an alpha-alkylidene beta-dicarbonyl compound in a highly stereoselective manner. The method complements the conventional Knoevenagel synthesis of this class of compounds as to the choice of the starting material and the scope and stereochemistry of the product.
Nakamura
Masaharu
M
Department of Chemistry, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. nakamura@chem.s.u-tokyo.ac.jp
Fujimoto
Taisuke
T
Endo
Kohei
K
Nakamura
Eiichi
E
D000475:Alkenes / Q000138:chemical synthesis* / Q000737:chemistry; D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D006868:Hydrolysis; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D013237:Stereoisomerism; D015032:Zinc / Q000737:chemistry*
D000475:Alkenes; D000480:Alkynes; D009942:Organometallic Compounds; D015032:Zinc