描述了铱催化的借氢过程在能够与高级醇形成 α-支化酮中的应用。为了促进该反应,邻位双取代的苯基和环丙基酮被认为是 CC 键形成的关键结构基序。在优化了关键催化步骤后,邻位二取代苯基产物可以通过反弗里德尔-克来福特酰化反应进一步操作,以产生合成有用的羧酸衍生物。相比之下,环丙基酮与几种亲核试剂进行同共轭加成,以提供进一步功能化的支化酮产物。
Hydrogen borrowing catalysis using 1° and 2° alcohols: Investigation and scope leading to α and β branched products
作者:James R. Frost、Choon Boon Cheong、Wasim M. Akhtar、Dimitri F.J. Caputo、Kirsten E. Christensen、Neil G. Stevenson、Timothy J. Donohoe
DOI:10.1016/j.tet.2021.132051
日期:2021.4
variety of ketonesusing 1° or 2° alcohols under hydrogen borrowing catalysis is described. Initial research focused on the α-alkylation of cyclopropyl ketones with higher 1° alcohols (i.e. larger than MeOH), leading to the formation of α-branchedproducts. Our search for additional substrates with which to explore this chemistry led us to discover that di-ortho-substituted aryl ketones were also privileged
描述了在氢借位催化下使用1°或2°醇对各种酮进行的烷基化。最初的研究集中在环丙酮与更高的1°醇(即大于MeOH)的α-烷基化反应上,导致形成α-支化产物。我们通过寻找其他底物来探索这种化学反应,使我们发现,二邻位取代的芳基酮也是特有的支架,其中Ph ∗(C 6 Me 5)酮是最佳选择。进一步的研究表明,该基序对于与2°醇形成β支链产物的烷基化至关重要,这也为研究非对映选择性和分子内氢借入过程提供了机会。
An efficient heterogenized palladium catalyst for N-alkylation of amines and α-alkylation of ketones using alcohols
Silica supported palladium–NiXantphos complex is an efficient and high turnover heterogeneous catalyst for N-alkylation of amines and α-alkylation of ketones using alcohols under neat conditions at 120–140 °C following hydrogen borrowing strategy.
Synthesis of Cyclopropanes via Hydrogen-Borrowing Catalysis
作者:Jessica L. Crompton、James R. Frost、Sam M. Rowe、Kirsten E. Christensen、Timothy J. Donohoe
DOI:10.1021/acs.orglett.3c01768
日期:2023.7.21
α-cyclopropanation of ketones using hydrogen borrowing (HB) catalysis is described. The transformation occurs via HB alkylation of a hindered ketone with subsequent intramolecular displacement of a pendant leaving group affording the cyclopropanated product. The leaving group can be installed in either the ketone or alcohol component of the HB system, giving access to α-cyclopropyl ketones via two complementary