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.
Ligand Control of the Cobalt-Catalysed 1,4-Hydrovinylation Reaction
very high regioselectivities for a number of terminal alkenes bearing various functional groups. In one case, the enantiomeric excess of a chiral product, i.e. a 3,5-dimethylhexa-1,4-diene derivative, was determined by chiral RP-HPLC to be 78% ee. The application of cobalt catalysts to the hydrovinylation of unsymmetrical alkenes and 1,3-dienes was investigated using modular phosphine-phosphite ligands