Tandem Acid/Pd‐Catalyzed Reductive Rearrangement of Glycol Derivatives
| Autor: | Tanno Schmidt, Ivana Fleischer, Prasad Kathe, Benjamin Ciszek |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Formic acid
rearrangement reduction 010402 general chemistry 01 natural sciences Aldehyde Medicinal chemistry Catalysis chemistry.chemical_compound homogenous catalysis Cascade reaction Formate tandem reactions chemistry.chemical_classification Full Paper 010405 organic chemistry Ligand Chemistry Organic Chemistry Leaving group Substrate (chemistry) General Chemistry Full Papers palladium 0104 chemical sciences Reaction Mechanisms |
| Zdroj: | Chemistry (Weinheim an Der Bergstrasse, Germany) |
| ISSN: | 1521-3765 0947-6539 |
| Popis: | Herein, we describe the acid/Pd‐tandem‐catalyzed transformation of glycol derivatives into terminal formic esters. Mechanistic investigations show that the substrate undergoes rearrangement to an aldehyde under [1,2] hydrogen migration and cleavage of an oxygen‐based leaving group. The leaving group is trapped as its formic ester, and the aldehyde is reduced and subsequently esterified to a formate. Whereas the rearrangement to the aldehyde is catalyzed by sulfonic acids, the reduction step requires a unique catalyst system comprising a PdII or Pd0 precursor in loadings as low as 0.75 mol % and α,α′‐bis(di‐tert‐butylphosphino)‐o‐xylene as ligand. The reduction step makes use of formic acid as an easy‐to‐handle transfer reductant. The substrate scope of the transformation encompasses both aromatic and aliphatic substrates and a variety of leaving groups. Easy to handle: Glycol derivatives are rearranged under the catalysis of sulfonic acids and subsequently reduced by a unique Pd/diphosphine (dtbpx=α,α′‐bis(di‐tert‐butylphosphino)‐o‐xylene) catalyst system with formic acid as transfer reductant. A [1,2] hydrogen shift leading to the subsequent formation of an aldehyde was identified as key step of the transformation, and a PdII–hydride complex is assumed as active hydrogenation catalyst. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
| Nepřihlášeným uživatelům se plný text nezobrazuje | K zobrazení výsledku je třeba se přihlásit. |