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。
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。
Stereoselective synthesis of enones from the reaction of aldehydes with sterically hindered dimethylaluminum enolates
作者:Zachary S. Sales、Roger Nassar、J. Jacob Morris、Kenneth W. Henderson
DOI:10.1016/j.jorganchem.2005.04.040
日期:2005.7
to reflux for several hours gave enone products in generally high conversions. The presumed aluminum aldolate intermediates were not detected by in situ monitoring studies and are presumably short-lived under the reaction conditions. The enone products from the addition reactions were formed predominantly as the E-isomers with good to excellent stereoselectivities.
Me 3 Al与甲基酮(2,4,6-R 3 -C 6 H 2)C(O)CH 3之间的等摩尔反应,其中R = Me或i Pr,导致烯醇化产物的排他性形成[ Me 2 AlOC(2,4,6-R 3 –C 6 H 2)CH 2 } 2 ],1和2,在甲苯溶液中加热至回流温度后。在这些反应中,Me 3 Al充当碱而不是亲核试剂的特性是由于酮的位阻特性。2的晶体学分析揭示了一种二聚体复合物,其中金属中心被烯醇化物阴离子桥接,与先前的研究1一致。向1和2的己烷溶液中添加一系列醛,然后加热回流数小时,得到的烯酮产物通常具有很高的转化率。推定铝醛酸酯中间体未通过原位监测研究检测到,并且在反应条件下可能是短命的。来自加成反应的烯酮产物主要形成为具有良好至优异的立体选择性的E-异构体。
BF<sub>3</sub>·OEt<sub>2</sub> catalyzed chemoselective CC bond cleavage of α,β-enones: an unexpected synthesis of 3-alkylated oxindoles and spiro-indolooxiranes
作者:Sengodagounder Muthusamy、Ammasi Prabu
DOI:10.1039/d1ob02002a
日期:——
of α,β-enones with diazoamides for the synthesis of 3-alkylated oxindoles is developed. Borontrifluoride etherate is found to be an effectivecatalyst for the chemoselective Cα–Cβ cleavage of enones to obtain 3-alkylated oxindoles. The product formation indicates a selective β-carbon elimination pathway of α,β-enones using the inexpensive BF3·OEt2 as a catalyst, transition metal-free conditions, an
New Compounds. 1-(2,4,6-Triisopropylphenyl)-3,3-diphenyl-1-propen-1-ol
作者:Reynold Fuson、A Rachlin
DOI:10.1021/ja01227a600
日期:1945.11
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。