Metal-Free Photoinduced Acylboration of [1.1.1]Propellane via Energy Transfer Catalysis

Highly strained 1,3-disubstituted bicyclo[1.1.1]pentanes(BCPs)have been established as bioisosteres of para-disubstitutedbenzene because they impart valuable pharmacokinetic properties. Herein,we demonstrate an energy transfer-mediated protocol for acylborationof [1.1.1]propellanes that allows the direct construction of variouscarbonyl species, such as carbamoyl-, carboxyl-, and acyl-, in tandemwith synthetically versatile pinacol boronate (Bpin) groups onto theBCP substructure under simple reaction conditions. Moreover, drug-likemolecules containing BCP boronates are further submitted to late-stagefunctionalization events. Several important transformations of theBpin functional group of BCP boronates, including photoinduced cross-couplingreactions of BCP-BF3K, derived from BCP-Bpin, were successfullyperformed to showcase the synthetic utility. Additionally, diverseand elaborate mechanistic investigations were performed to providemechanistic insights, and a plausible reaction mechanism is proposed.