Iron Catalysis in Organic Synthesis: A Critical Assessment of What It Takes To Make This Base Metal a Multitasking Champion

Abstract

The current status of homogeneous iron catalysis in organic chemistry is contemplated, as are the reasons why this particular research area only recently starts challenging the enduring dominance of the late and mostly noble metals over the field. Centered in the middle of the d-block and able to support formal oxidation states ranging from −II to +VI, iron catalysts hold the promise of being able to encompass organic synthesis at large. They are expected to serve reductive as well as oxidative regimes, can emulate “noble tasks”, but are also able to adopt “early” transition metal character. Since a comprehensive coverage of this multidimensional agenda is beyond the scope of an Outlook anyway, emphasis is laid in this article on the analysis of the factors that perhaps allow one to control the multifarious chemical nature of this earth-abundant metal. The challenges are significant, not least at the analytical frontier; their mastery mandates a mindset that differs from the routines that most organic chemists interested in (noble metal) catalysis tend to cultivate. This aspect notwithstanding, it is safe to predict that homogeneous iron catalysis bears the chance to enable a responsible paradigm for chemical synthesis and a sustained catalyst economy, while potentially providing substantial economic advantages. This promise will spur the systematic and in-depth investigations that it takes to upgrade this research area to strategy-level status in organic chemistry and beyond.

2‐Methyltetrahydrofuran: A Green Solvent for Iron‐Catalyzed Cross‐Coupling Reactions

“…[1][2][3][4][5] Selectivem ethods for cross-coupling reactions in green, renewables olvents are essentialt or educe environmental damage. The major challenge to maintain full sustainabilityo ft he process is the identification of green and renewable solvents that can be harnessed to replace the conventional solvents for this highly attractive reaction.…”

A Physical‐Inorganic Approach for the Elucidation of Active Iron Species and Mechanism in Iron‐Catalyzed Cross‐Coupling

“…[26–29] Recent reviews further highlight the success of iron catalysts in organic synthesis to obtain cross-coupled products. [30–31] …”

From Mechanisms in Homogeneous Metal Catalysis to Applications in Chemical Synthesis

“…Mechanistic insights are crucial for understanding and in this way important for the further development of multifaceted transition metal mediated transformations [16][17][18][19][20][21]. Short-living, sensitive and highly reactive intermediates as well as different oxidation-and spin-states [17,20,21] often complicate mechanistic analyses.…”

“…Short-living, sensitive and highly reactive intermediates as well as different oxidation-and spin-states [17,20,21] often complicate mechanistic analyses. Steadily advancing experimental techniques (spectroscopy, electrochemical methods, X-ray analysis, etc.)…”