Radical Replacement\nProcess for Ligated Boryl Radical-Mediated\nActivation of Unactivated Alkyl Chlorides for C(sp<sup>3</sup>)–C(sp<sup>3</sup>) Bond Formation

The ligated boryl radical (LBR) has emerged as a potent\ntool for\nactivating alkyl halides in radical transformations through halogen-atom\ntransfer (XAT). However, unactivated alkyl chlorides still present\nan open challenge for this strategy. We herein describe a new activation\nmode of the LBR for the activation of unactivated alkyl chlorides\nto construct a C(sp<sup>3</sup>)–C(sp<sup>3</sup>) bond. Mechanistic\nstudies reveal that the success of the protocol relies on a radical\nreplacement process between the LBR and unactivated alkyl chloride,\nforming an alkyl borane intermediate as the alkyl radical precursor.\nAided with the additive K<sub>3</sub>PO<sub>4</sub>, the alkyl borane\nthen undergoes one-electron oxidation, generating an alkyl radical.\nThe incorporation of the radical replacement activation model to activate\nunactivated alkyl chlorides significantly enriches LBR chemistry,\nwhich has been applied to activate alkyl iodides, alkyl bromides,\nand activated alkyl chlorides via XAT.