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。
Iron-Catalyzed α-Alkylation of Ketones with Secondary Alcohols: Access to β-Disubstituted Carbonyl Compounds
作者:Léo Bettoni、Sylvain Gaillard、Jean-Luc Renaud
DOI:10.1021/acs.orglett.0c00549
日期:2020.3.6
borrowing hydrogen strategy has been applied in the synthesis of β-branched carbonylcompounds. Various secondary benzylic and aliphatic alcohols have been used as alkylating reagents under mild reaction conditions. The ketones have been isolated in good to excellent yield. Deuterium labeling experiments provide evidence that the alcohol is the hydride source in this reaction and that no reversible step or
Although α‐alkylation of ketones with primary alcohols by transition‐metal catalysis is well‐known, the same process with secondaryalcohols is arduous and complicated by self‐condensation. Herein a well‐defined, high‐valence cobalt(III)‐catalyst was applied for successful α‐alkylation of ketones with secondaryalcohols. A wide‐variety of secondaryalcohols, which include cyclic, acyclic, symmetrical
Hydrogen Borrowing Catalysis with Secondary Alcohols: A New Route for the Generation of β-Branched Carbonyl Compounds
作者:Wasim M. Akhtar、Choon Boon Cheong、James R. Frost、Kirsten E. Christensen、Neil G. Stevenson、Timothy J. Donohoe
DOI:10.1021/jacs.6b12840
日期:2017.2.22
hydrogen borrowing reaction employing secondary alcohols and Ph* (Me5C6) ketones to give β-branched carbonyl products is described (21 examples). This new C-C bond forming process requires low loadings of [Cp*IrCl2]2, relatively low temperatures, and up to 2.0 equiv of the secondary alcohol. Substrate-induced diastereoselectivity was observed, and this represents the firstexample of a diastereoselective
Transition metal free α-C-alkylation of ketones using secondary alcohols
作者:Mubarak B. Dambatta、Joseph Santos、Robert R.A. Bolt、Louis C. Morrill
DOI:10.1016/j.tet.2020.131571
日期:2020.11
A base-mediated α-C-alkylation of ketones with secondaryalcohols has been developed. This transition metal free approach employs KOt-Bu as the base and exhibits a broad scope, allowing a range of commodity aliphatic secondaryalcohols and 1-arylethanols to be employed as alkylating agents. Aryl methyl ketones undergo selective mono-α-C-alkylation in high isolated yields (23 examples, 65% average yield)
已经开发了用仲醇进行的碱介导的酮的α- C-烷基化。这种不含过渡金属的方法采用KO t -Bu作为碱,并且具有广泛的应用范围,允许将多种商品脂族仲醇和1-芳基乙醇用作烷基化剂。芳基甲基酮经历选择性单α -C烷基化在高分离产率(23个实例中,65%平均产率)。