Iron-Catalyzed Direct Alkenylation of 2-Substituted Azaarenes with N-Sulfonyl Aldimines via C–H Bond Activation

Abstract

A novel iron-catalyzed alkenylation of 2-substituted azaarenes through sp(3) C-H bond activation has been developed. A favorable E2-elimination is proposed as a key step to cleavage of C-H and C-N bonds for the construction of a C═C bond in high stereoselectivity. This transformation represents an efficient way to synthesize 2-alkenylated azaarenes from simple starting materials.

Iron Catalysis in Organic Synthesis

“…961 Using catalytic amounts of iron(II) acetate, they synthesized 2-alkenylated azaarenes with high E-stereoselectivity and in moderate to high yields.…”

Strategy for Stereoselective Metal‐free α‐Functionalization of 2‐Azaaryl Acetates with N‐Boc Imines

“…Firstly, the majority of the methods reported until now are racemic. Secondly, 2‐methylazaarenes, for example, 2‐methyl pyridines are the substrates of choice to generate a single stereocenter, and finally, high temperatures are needed for reaction success, a condition that may cause subsequent C−N elimination ,…”

Iron-Catalyzed Cross-Dehydrogenative-Coupling Reactions

“…The reaction is initiated by formation of enamine A in situ [24][25][26][27][28]. Subsequently, the reaction of A with the iminium species B [29][30][31][32], which is generated by the Fe II species, the amide compound, and K 2 S 2 O 8 , gives the intermediate C. Then, elimination of N-methylacetamide from C affords the vinylated product and regenerates the Fe III species.…”