Efficient and general alkyl-alkyl Suzuki-Miyaura cross-coupling enabled by an iron-based catalyst

Alkyl substituted coupling partners are valuable reagents for cross-coupling, leading to more diverse chemical spacetypical in many natural products. However, the use of sp³-hybridized substrates continues to remain a formidable challenge for synthetic chemists due to competitive b-hydride elimination. Due to this detrimental reactivity, this subset of cross-coupling remains the most elusive of cross coupling reactions. To help fill this synthetic gap, a Suzuki-Miyaura cross-coupling reaction between unactivated alkyl halides and primary and secondary alkyl 9-BBN reagents catalyzed by a fluorinated b-diketiminate iron complex was developed. The reaction affords good to excellent yields of cross-coupled product and provides access to valuable methylation reactions. Additionally, mechanistic studies will be presented that provide insight into the mechanistic underpinnings of the cross-coupling reaction. This iron-catalyzed reaction expandsthe substrates that can engage in this difficult transformation, providing complementary reactivity to commonly-used nickel catalysts.