Cobalt‐Catalyzed Enantioselective Hydrogenation of Trisubstituted Carbocyclic Olefins: An Access to Chiral Cyclic Amides
Soumyadeep Chakrabortty, Katharina Konieczny, Felix J. de Zwart, Eduard O. Bobylev, Eszter Mikó–Baráth, Sergey Tin, Bernd Müller, Joost N. H. Reek, Bas de Bruin, Johannes G. de Vries
Abstract
Abstract The enantioselective hydrogenation of cyclic enamides has been achieved using an earth‐abundant cobalt‐bisphosphine catalyst. Using CoCl 2 /( S,S )‐Ph‐BPE, several trisubstituted carbocyclic enamides were reduced with high activity and excellent enantioselectivity (up to 99 %) to the corresponding saturated amides. The methodology can be extended to the synthesis of chiral amines by base hydrolysis of the hydrogenation products. Preliminary mechanistic investigations reveal the presence of a high spin cobalt (II) species in the catalytic cycle. We propose that the hydrogenation of the carbon‐carbon double bond proceeds via a sigma‐bond‐metathesis pathway.