General and Practical Route to Diverse 1,3-(Difluoro)alkyl bicyclo[1.1.1]-Aryl Pentanes Enabled by an Fe-Catalyzed Multicomponent Radical Coupling

Bicyclo[1.1.1]pentanes (BCPs) are of great interest to the agrochemical, materials, and pharmaceutical industries. In particular, synthetic methods to access 1,3-dicarbosubsituted BCP-aryls have recently been developed but most protocols rely on stepwise C-C bond formation via initial manipulation of BCP core to make the BCP-electrophile or -nucleophile followed by a second step (e.g., transition-metal mediated cross-coupling step) to form the second key BCP-aryl bond. Moreover, despite prevalence of C-F bonds in bioactive compounds, one pot, multicomponent cross-coupling methods to directly functionalize BCP to the corresponding fluoroalkyl BCP-aryl scaffolds are lacking. In this work, we describe a conceptual different approach to access diverse (fluoro)alkyl BCP-aryls at low temperatures and fast reaction times enabled by an iron-catalyzed multicomponent radical cross-coupling reaction from readily available (fluoro)alkyl halides, bicyclo[1.1.1]pentane, and Grignard reagents. Further, experimental and computational mechanistic studies provide insights into mechanism and ligand effects on the nature of C-C bond formation. Finally, these studies are used to develop a new method to rapidly access synthetic versatile 1-(fluoro)alkyl,3-bromo and -iodo BCPs via bisphosphine iron catalysis.