| Affiliation: | 1. Institute of Organic Chemistry, Faculty of Mathematics and Natural Sciences, Eberhard-Karls University Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany current address: Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland;2. Institute of Organic Chemistry, Faculty of Mathematics and Natural Sciences, Eberhard-Karls University Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany |
| Abstract: | 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. |
