Site-Selective (Z)-α-Borylalkenyl Copper Systems for Nucleophilic Stereodefined Allylic Coupling

Abstract

1,1-Diborylalkenes can be transformed into (Z)-skipped dienes through Cu^I -phosphine catalyzed allylic coupling reactions. The energetically preferred formation of (Z)-α-borylalkenyl copper (I) species and the subsequent nucleophilic attack, explains the stereoselective nucleophilic substitution with allyl bromides. The eventual treatment of (Z)-skipped dienes with NaO^t Bu promotes cyclization/aromatization patterns via enyne intermediates.

Keywords: 1,1-Diborylalkenes; Allylic Coupling; Copper; Skipped Dienes; Stereoselective Synthesis.