Iron-catalyzed reactions organic synthesis

The chemistry of iron has been reviewed in COMC (1982) and COMC (1995)312-314 as well as in Comprehensive Coordination Chemistry 7/.315 More recent reviews cover iron-catalyzed transformations with samarium(ll) iodide,18d the chemistry of tricarbonyliron-diene complexes,316 and iron-catalyzed reactions in organic synthesis in general.317... 

VII. APPLICATIONS OF IRON-CATALYZED REACTIONS OF GRIGNARD REAGENTS IN ORGANIC SYNTHESIS... 

Review of iron-catalyzed reactions in organic synthesis Bolm, C. Legros, J. ... 

The direct reductive amination (DRA) is a useful method for the synthesis of amino derivatives from carbonyl compounds, amines, and H2. Precious-metal (Ru [130-132], Rh [133-137], Ir [138-142], Pd [143]) catalyzed reactions are well known to date. The first Fe-catalyzed DRA reaction was reported by Bhanage and coworkers in 2008 (Scheme 42) [144]. Although the reaction conditions are not mild (high temperature, moderate H2 pressure), the hydrogenation of imines and/or enam-ines, which are generated by reaction of organic carbonyl compounds with amines, produces various substituted aryl and/or alkyl amines. A dihydrogen or dihydride iron complex was proposed as a reactive intermediate within the catalytic cycle. 

Significant progress has been made in the fields of ruthenium-, iron-, iridium-, rhodium-, and copper-catalyzed cascade reactions. Noticeably, these transition metal catalysts are critically important in numerous commercial chemical processes. Discoveries of new cascade processes along with improvements in the activity, selectivity, and scope of these catalysts could drastically reduce the environmental impact and increase the sustainability of chemical reactions. From the viewpoint of practical applications, iron and copper are the most abundant metals on Earth and, consequently, inexpensive and environmentally friendly. Moreover, many iron and copper salts and complexes are commercially available or are described in the literature. Due to these advantages, the development and applications of iron- and copper-catalyzed cascade reactions are becoming a thriving area of organic synthesis chemistry. 

This enzyme [EC 1.2.99.2], also known as acetyl-CoA synthase, catalyzes the reaction of carbon monoxide with water and an acceptor to produce carbon dioxide and the reduced acceptor. The cofactors of this enzyme include nickel and zinc ions as well as non-heme iron. Methyl viologen can act as the acceptor substrate. The enzyme is isolated from Clostridium sp. Interestingly, it also catalyzes an exchange reaction of carbon between Cl of acetyl-CoA and carbon monoxide. The protein participates in the synthesis of acetyl-CoA from carbon dioxide and hydrogen in the organisms. 

Selective cross-coupling reactions between C(sp ) and C(5p ) centers had been one of the most difficult tasks in carbon-carbon bond synthesis until the early 1970s, when it was first reported that iron, nickel, palladium and copper - catalysts are extremely effective for cross-coupling of Grignard reagents with organic halides. Now, nearly 20 years later, transition metal catalyz cross-coupling has become the reaction of first choice for this purpose. 

---