A Broadly Applicable Alkyl-Alkyl Suzuki-Miyaura Cross-Coupling Reaction Catalyzed by an Iron-Based Complex

An iron-based catalyst for the Suzuki-Miyaura reaction between two sp3-hybridized substrates has been developed for a broad range of unactivated alkyl halides and alkyl boranes. Key to success was using a Cs-symmetric beta-diketiminate ligand that contained a tert-butyl and trifluoromethyl functionalized backbone. The breadth of the cross-coupling reaction was demonstrated with high yields of cross-coupled products observed from reactions using primary and secondary alkyl bromides as well as primary alkyl boranes and even some secondary alkyl boranes. Complementary methylation reactions using methyl iodide or methyl-9-BBN was also possible. The facile diversification of a steroid derivative using these reactions demonstrated the synthetic utility of such complementary cross coupling reactions.