The Mechanism and an Improved Asymmetric Allylboration of Ketones Catalyzed by Chiral Biphenols
作者:David S. Barnett、Philip N. Moquist、Scott E. Schaus
DOI:10.1002/anie.200904715
日期:2009.11.2
Giving it a boost: A mechanistic study of the enantioselective asymmetric titled reaction with allyldiisopropoxyborane catalyzed by chiralbiphenols revealed a key ligand exchange process which liberates isopropyl alcohol. The addition of iPrOH to the reaction increases the overall rate and enantioselectivity. As a result an improved reaction, employing allyldioxaborinane with 1 and tBuOH, resulted
Catalytic Use of Indium(0) for Carbon−Carbon Bond Transformations in Water: General Catalytic Allylations of Ketones with Allylboronates
作者:Uwe Schneider、Masaharu Ueno、Shu̅ Kobayashi
DOI:10.1021/ja804182j
日期:2008.10.22
We have discovered the unprecedented catalytic use of In(0) for catalytic C-C bond transformations. Remarkably, these generalcatalytic allylations of ketones proceeded smoothly in water as a sole solvent under mild conditions, and water proved to be essential for these reactions. Both the displayed substrate scope and the functional group tolerance were excellent. Importantly, the In metal catalyst
我们发现了 In(0) 在催化 CC 键转换中前所未有的催化用途。值得注意的是,这些酮的一般催化烯丙基化反应在温和条件下在作为唯一溶剂的水中顺利进行,并且水被证明是这些反应必不可少的。显示的底物范围和官能团耐受性都非常好。重要的是,In 金属催化剂可以很容易地回收和重复使用,而不会损失催化活性。此外,当使用 α 取代的烯丙基硼酸酯时,观察到不寻常的结构选择性,仅提供正式的 α 加合物。此外,得到的叔均烯丙基醇具有极高的非对映选择性。
Allylation of Carbonyl Compounds by Allylic Acetates Using a Cobalt Halide as Catalyst
作者:Corinne Gosmini、Paulo Gomes、Jacques Périchon
DOI:10.1055/s-2003-40999
日期:——
In acetonitrile as solvent and in the presence of a simple cobalt halide as catalyst, the reduction by zinc dust of a mixture of aldehydes or ketones and allylic acetates affords the corresponding homoallylic alcohols in good yields.
Coupling reactions of α-chloroesters with aryl halides (α-arylation) or carbonyl compounds (Reformatsky) using nickel catalyst allow, under mild conditions, the preparation of various functionalized aryl propionic acid derivatives or β-hydroxyesters. In the synthesis of aryl propionic acid derivatives, the process is efficient with aryl halides bearing either electron-withdrawing or electron-donating