Multicomponent Cyclopropane Synthesis Enabled by Cu-Catalyzed Cyclopropene Carbometalation with Organoboron Reagent: Enantioselective Modular Access to Polysubstituted 2-Arylcyclopropylamines

The use of functional-group-tolerant organo-boron in lieu of basic organometallic reagents in base-metal catalyzed cyclopropene carbometalation opens three-component cyclopropane synthesis, as exemplified by the modular assembly of the highly medicinally relevant 2-arylcyclopropylamine (ACPA) framework via stereoselective carboamination. The highly enantioselective version has been realized to afford enantioenriched ACPAs with up to all three cyclopropyl carbons as stererogenic centers in one operation, representing the first example of enantioselective multicomponent cyclopropane synthesis. The reaction significantly improves the efficiency of ACPA synthesis and may inspire the development of other multicomponent cyclopropane syntheses beyond amination.