Development of iridium-catalyzed asymmetric hydrogenation: New catalysts, new substrate scope

Abstract

Development of iridium-catalyzed asymmetric hydrogenation: New catalysts, new substrate scope.. The asymmetric hydrogenation of olefins is a tremendously powerful tool used to synthesize chiral molecules. The field was pioneered using rhodium--and ruthenium--based catalysts; however, catalysts based on both of these metals suffer from limitations, such as the need for directing substituents near or even adjacent to the olefin. Iridium--based catalysts do not suffer from this flaw and can thus hydrogenate a wide variety of olefins, including some tetra substituted ones. It is also possible for iridium--based catalysts to hydrogenate hetero--π bonds such as those found in hetero--aromatic rings. This review summarizes the contributions made to this field by our research group over the past few years. Keywords: Asymmetric catalysis, Iridium, Hydrogenation, Alkenes Graphical Abstract: Journal of Organometallic Chemistry

DFT Methods to Study the Reaction Mechanism of Iridium‐Catalyzed Hydrogenation of Olefins: Which Functional Should be Chosen?

“…[1][2][3][4][5][6][7][8][9][10] The first highly active catalyst for the hydrogenation of unfunctionalized alkenes wasana chiral Ir/P,N complex (Figure 1), whichw as reported by Crabtree and co-workers in 1977. [1][2][3][4][5][6][7][8][9][10] The first highly active catalyst for the hydrogenation of unfunctionalized alkenes wasana chiral Ir/P,N complex (Figure 1), whichw as reported by Crabtree and co-workers in 1977.…”

“…During the last decade, iridium-based hydrogenation catalysts have attractedmuch attention, because of their ready availability,h igh reactivity,a nd excellent enantioselectivity in asymmetric hydrogenations of olefins. [1][2][3][4][5][6][7][8][9][10] The first highly active catalyst for the hydrogenation of unfunctionalized alkenes wasana chiral Ir/P,N complex (Figure 1), whichw as reported by Crabtree and co-workers in 1977. [11] Twenty years later,t he first chiral mimic of Crabtree's catalyst with ap hosphinooxazoline (PHOX) ligand was developed by Pfaltz and co-workers( Figure1), who successfully realized the efficient asymmetric conversion of substrates.…”

“…[11] Twenty years later,t he first chiral mimic of Crabtree's catalyst with ap hosphinooxazoline (PHOX) ligand was developed by Pfaltz and co-workers( Figure1), who successfully realized the efficient asymmetric conversion of substrates. [1][2][3][4][5][6][7][8][9][10] However,i nc ontrastt or elatedr uthenium-based and rhodium-based catalytic hydrogenation, [15][16][17][18][19][20][21][22] the mechanism of the iridium-catalyzed hydrogenation is still not fully clarified. [1][2][3][4][5][6][7][8][9][10] However,i nc ontrastt or elatedr uthenium-based and rhodium-based catalytic hydrogenation, [15][16][17][18][19][20][21][22] the mechanism of the iridium-catalyzed hydrogenation is still not fully clarified.…”

“…[12][13][14] Initiated by this groundbreaking discovery, hundreds of chiral iridium-based catalystsh ave been developed and tested for variousalkene hydrogenations. [1][2][3][4][5][6][7][8][9][10] However,i nc ontrastt or elatedr uthenium-based and rhodium-based catalytic hydrogenation, [15][16][17][18][19][20][21][22] the mechanism of the iridium-catalyzed hydrogenation is still not fully clarified. [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] In this regard, theoretical computation and modeling could potentially contribute to solving this conundrum, due to the lack of much relevant experimentald ata.…”

Optimized Scalable Synthesis of Chiral Iridium Pyridyl‐Phosphinite (Pyridophos) Catalysts

“…[13] Other groups as well have developed efficient ligand systems for Ir-catalyzed asymmetric hydrogenation. [14][15][16][17][18][19][20][21] Selected examples are shown in Figure 1. In addition to chiral P,N ligands, also other heterodonor ligands were successfully applied, such as P-thioether ligands [22 -24] and C,N ligands derived from N-heterocyclic carbenes.…”