Schull Cullen R, McGill Matthew J, Renteria-Gómez Ángel, Mukherjee Poulami, Tyndall Samuel B, Shoemaker Aaron H, Wasielewski Michael R, Gutierrez Osvaldo, Scheidt Karl A
Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA.
Department of Chemistry and Biochemistry, University of California, 607 Charles E. Young Drive, East Los Angeles, Los Angeles, CA, 90095, USA.
Angew Chem Int Ed Engl. 2025 Aug 4:e202510162. doi: 10.1002/anie.202510162.
Alkyl organoboron compounds are versatile synthons in organic synthesis, enabling rapid access to a variety of carbon─carbon and carbon-heteroatom bonds. As such, strategies to efficiently access carbon-boron bonds from simple chemical feedstocks are highly desirable. The radical borylation of alkyl bromides presents an attractive approach. However, the activation of alkyl bromides typically requires strong reductants or transition-metal catalysts. Herein, we report a metal-free radical borylation strategy of various alkyl bromides utilizing a photoinduced silyl radical to mediate a halogen-atom transfer process. This method demonstrates broad utility and functional group tolerance among various primary, secondary, and tertiary unactivated alkyl bromides and can facilitate the functionalization of pharmaceutically relevant motifs. Mechanistic and computational studies support a radical-chain pathway involving a silyl radical-mediated halogen-atom transfer.
烷基有机硼化合物是有机合成中用途广泛的合成子，能够快速构建各种碳-碳键和碳-杂原子键。因此，人们非常希望能有从简单化学原料高效构建碳-硼键的策略。烷基溴的自由基硼化反应是一种很有吸引力的方法。然而，活化烷基溴通常需要强还原剂或过渡金属催化剂。在此，我们报道了一种无金属的各种烷基溴自由基硼化策略，该策略利用光诱导硅自由基介导卤原子转移过程。该方法在各种伯、仲和叔未活化烷基溴中显示出广泛的实用性和官能团耐受性，并且能够促进与药物相关基序的官能团化。机理和计算研究支持了一个涉及硅自由基介导卤原子转移的自由基链反应途径。
