Gaining Absolute Control of the Regiochemistry in the Cobalt-Catalyzed 1,4-Hydrovinylation Reaction
摘要:
The absolute control of the regiochemistry of a cobalt-catalyzed 1,4-hydrovinylation reaction is achieved by alternation of the ligands applied. While the dppe/dppp ligands led to the formation of the branched product, the herein described application of the SchmalzPhos ligand generates the corresponding linear product in both excellent yields and regioselectivities. The catalyst system exhibits a high tolerance toward functional groups, and the very mild reaction conditions allow the synthesis of 1,4-dienes without isomerization into conjugated systems.
Nickel-catalysed addition of organoboronates to 1,3-dienesElectronic supplementary information (ESI) available: 1H NMR spectra and MS data. See http://www.rsc.org/suppdata/cc/b2/b207185a/
Aryl- and alkenylboronates were found to add to 1,3-dienes in the presence of a catalytic amount of bis(1,5-cyclooctadiene)nickel, where a proton source in combination with a solvent considerably controls the regioselectivity.
The absolute control of the regiochemistry of a cobalt-catalyzed 1,4-hydrovinylation reaction is achieved by alternation of the ligands applied. While the dppe/dppp ligands led to the formation of the branched product, the herein described application of the SchmalzPhos ligand generates the corresponding linear product in both excellent yields and regioselectivities. The catalyst system exhibits a high tolerance toward functional groups, and the very mild reaction conditions allow the synthesis of 1,4-dienes without isomerization into conjugated systems.