polycyclic indoline-annulated normal to medium-size rings through dearomatization of indole via a tandem 1,2-acyloxy migration/intramolecular [3 + 2] cycloaddition process is described. The pentacyclic skeleton of strychnine could be synthesized via this tandemcycloaddition and a further Mannich reaction. This approach would provide a novel strategy to the synthesis of strychons alkaloids.
Stereoselective Synthesis of Cyclohexanes via an Iridium Catalyzed (5 + 1) Annulation Strategy
作者:Wasim M. Akhtar、Roly J. Armstrong、James R. Frost、Neil G. Stevenson、Timothy J. Donohoe
DOI:10.1021/jacs.8b07776
日期:2018.9.26
An iridium catalyzed method for the synthesis of functionalized cyclohexanes from methyl ketones and 1,5-diols is described. This process operates by two sequential hydrogen borrowing reactions, providing direct access to multisubstituted cyclic products with high levels of stereocontrol. This methodology represents a novel (5 + 1) strategy for the stereoselective construction of the cyclohexane core
A Phosphine-Free Manganese Catalyst Enables Stereoselective Synthesis of (1 + <i>n</i>)-Membered Cycloalkanes from Methyl Ketones and 1,<i>n</i>-Diols
作者:Akash Jana、Kuhali Das、Abhishek Kundu、Pradip Ramdas Thorve、Debashis Adhikari、Biplab Maji
DOI:10.1021/acscatal.9b05567
日期:2020.2.21
Herein, we report the stereoselective synthesis of (1 + n)-membered cycloalkane from methyl ketone and 1,n-diol. A manganese(I) complex bearing a phosphine-free ligand catalyzed the reaction, which involved the formation of two C–C bonds via a sequence of intermolecular- and intramolecular-borrowing hydrogenation reactions. It produces 2 mol of water as the sole byproduct, making the process atom economical
Stereoselective synthesis of alicyclic ketones: A hydrogen borrowing approach
作者:Roly J. Armstrong、Wasim M. Akhtar、James R. Frost、Kirsten E. Christensen、Neil G. Stevenson、Timothy J. Donohoe
DOI:10.1016/j.tet.2019.130680
日期:2019.11
A highly diastereoselective annulation strategy for the synthesis of alicyclic ketones from diols and pentamethylacetophenone is described. This process is mediated by a commercially available iridium(III) catalyst, and provides efficient access to a wide range of cyclopentane and cyclohexane products with high levels of stereoselectivity. The origins of diastereoselectivity in the annulation reaction
A phosphine-free iron complex-catalyzed synthesis of cycloalkanes <i>via</i> the borrowing hydrogen strategy
作者:Léo Bettoni、Sylvain Gaillard、Jean-Luc Renaud
DOI:10.1039/d0cc05840h
日期:——
Herein we report a diaminocyclopentadienone iron tricarbonylcomplex catalyzed synthesis of substituted cyclopentane, cyclohexane and cycloheptane compoundsusing the borrowing hydrogen strategy in the presence of various substituted primary and secondary 1,n diols as alkylating reagents. Deuterium labeling experiments confirm that the diols were the hydride source in this cascade process.