Cross-pinacol-type coupling reactions between alpha,beta-unsaturated ketones and aldehydes with low-valent metals.
Treatment of an alpha,beta-unsaturated ketone and an aldehyde with chromium(II) chloride and R(3)SiCl in DMF gives cross-pinacol-type coupling products, 1,2-diols selectively. The anti/syn ratios of the produced 1,2-diols are shown to depend on the reaction temperature: at lower temperatures, the anti adduct is produced selectively, but at higher temperatures, the anti/syn ratios gradually decrease. When a combination of manganese and a catalytic amount of lead are used instead of chromium(II), 1,6-diketone, a dimer of the alpha,beta-unsaturated ketone, is produced selectively.
Takai
Kazuhiko
K
Department of Applied Chemistry, Faculty of Engineering, Okayama University, Japan. ktakai@cc.okayama-u.ac.jp
Morita
Ryotaro
R
Matsushita
Hiroshi
H
Toratsu
Chika
C
D000447:Aldehydes / Q000737:chemistry*; D007202:Indicators and Reagents; D007659:Ketones / Q000737:chemistry*; D008670:Metals / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D013237:Stereoisomerism
D000447:Aldehydes; D007202:Indicators and Reagents; D007659:Ketones; D008670:Metals