Abstract
This article presents our findings on catalytic ortho-selective C–C bond formations
through the cleavage of C–H bonds in aromatic ketones using low-valent iron-phosphine
complexes. We describe four types of catalytic transformations that convert C–H bonds
into C–C bonds. Reactions involving terminal alkenes, such as vinyl and allylsilanes,
aliphatic alkenes, styrenes, vinyl ethers, and enamines, yield the corresponding linear
alkylation products. The coupling reaction using methylenecyclopropanes yields homoallylation
products via alkene 1,2-insertion, followed by β-carbon elimination. The C–H alkenylation
can be achieved by the reaction with internal alkynes. The use of 1,n-enynes (where n = 6, 7) as coupling partners for the C–H bond led to hydroarylative enyne cyclization
products. The results of deuterium-labeling experiments of these reactions are also
discussed.
Keywords
Low-valent iron-phosphine complex - C–H activation - C–C bond formation - Aromatic
ketone - Alkenes - Alkynes - 1,
n-Enynes