Pd-catalyzed regioselective hydroesterification of 3-allyl-2-hydroxynaphthoquinones: Easy access to linear or branched naphthoquinone esters

Pd-catalyzed regioselective hydroesterification of 3-allyl-2-hydroxynaphthoquinone derivatives has been reported. It is possible to control the regioselective hydroesterification of allyl naphthoquinone based on the ligand bite angle. Linear or branched esters can be obtained with excellent regioselectivity. [Display omitted] •Regioselective hydroesterification of allyl naphthoquinones was explored.•The regioselective hydroesterification of allyl naphthoquinone can be controlled based on the ligand bite angle.•Cytotoxicity testing of the esters obtained against tumor cells provides relevant information.•Control reactions provide support for a proposed catalytic cycle. The successful hydroesterification of 3-allyl-2-hydroxynapthoquinones is presented, providing excellent regioselectivity of the linear and branched esters. The Pd(OAc)2/dppf catalytic system was used to prepare a series of linear naphthoquinone esters with high regioselectivity. A slight modification of the initial conditions afforded branched esters with high regioselectivity using a PdCl2/dppe combination. Control experiments facilitated observation of a correlation between the hydroxy group present on the substrate and the selectivity of the reaction. In addition, a cytotoxic test was conducted on the synthesized esters against six tumor cell lines, which provided valuable information about their biological activity.