Access to Electron-Deficient 2,2-Disubstituted Chromanes: A Highly Regioselective One-Pot Synthesis via an Inverse-Electron-Demand [4 + 2] Cycloaddition of <i>ortho</i>-Quinone Methides
We report the one-pot synthesis of 2,2-disubstituted chromanes with electron-withdrawing substituents. This reaction provides a simple yet efficient route to a wide range of electron-deficient chromanes in highyield and excellent regioselectivity. The reaction of salicylaldehyde with 1,1-disubstituted ethylenes smoothly furnishes these electron-deficient chromanes, which can be further transformed
Temperature-controlled divergent synthesis of 4-alkoxy- or 4-alkenyl-chromanes via inverse electron-demand cycloaddition with in situ generated ortho-quinone methides
The temperature-controlled divergent synthesis of 4-alkoxy- or 4-alkenyl-chromanes via inverse electron-demand cycloaddition with in situ generated ortho-quinone methides under identical reaction conditions except for thermal condition has been developed. At room temperature, the reaction generated 4-methoxychromanes, whereas the reaction performed at room temperature to 100 °C gave 4-alkenylchromanes
Contra-thermodynamic Olefin Isomerization by Chain-Walking Hydroboration and Dehydroboration
作者:Steven Hanna、Brandon Bloomer、Nicodemo R. Ciccia、Trevor W. Butcher、Richard J. Conk、John F. Hartwig
DOI:10.1021/acs.orglett.1c03124
日期:2022.2.4
chain-walking hydroboration to create a one-pot, contra-thermodynamic, short- or long-range isomerization of internal olefins to terminal olefins. This dehydroboration occurs by a sequence comprising activation with a nucleophile, iodination, and base-promoted elimination. The isomerization proceeds at room temperature without the need for a fluoride base, and the substrate scope of this isomerization is expanded