In the presence of catalytic amounts of GaCl3 (10 mol%) and 2,6-di(t-butyl)-4-methylpyridine (10 mol%), five- or six-membered ring ketones possessing α,α′-disubstituents are ethenylated at the α-carbon with triethylsilylethyne at 180 °C. The roles of the base are to inhibit decomposition of the products and to promote protodegallation of the organogallium intermediates.
在催化量的 GaCl3(10 摩尔%)和 2,6-二(叔丁基)-4-甲基吡啶(10 摩尔%)存在下,具有δ,δ′-二取代基的五元或六元环酮在 180 °C 下与三乙基硅基乙炔在δ-碳处发生乙烯基化反应。碱的作用是抑制产物的分解和促进有机镓中间体的原降解。
Asymmetric deprotonation: a new route to chiral compounds
作者:Nigel S. Simpkins
DOI:10.1039/c39860000088
日期:——
Enantioselective deprotonation of symmetrically substituted ketones under kinetically controlled conditions provides chiral products in up to 74% enantiomeric excess.
在动力学控制的条件下,对称取代的酮的对映选择性去质子化可提供高达74%对映体过量的手性产物。
Iridium-Catalyzed Double Asymmetric Hydrogenation of 2,5-Dialkylienecyclopentanones for the Synthesis of Chiral Cyclopentanones
Herein, we report an efficient iridium-catalyzed double asymmetrichydrogenation of 2,5-dialkylienecyclopentanones, delivering the chiral 2,5-disubstituted cyclopentanones in excellent yields and stereoselectivities. The results of the kinetic experiments and control experiments indicated that the two C═C bonds were hydrogenated in a stepwise manner and the second stereocenter was synergistically controlled
A composition for topical application comprising at least one surfactant having a nitrogen atom in the moiety thereof and at least one compound selected from the group consisting of cyclohexane and the derivatives thereof, cyclohexene and the derivatives thereof, and cyclohexanone and the derivatives thereof.