Novel double substrate insertion versus isocyanate extrusion in reactions of imidotitanium complexes with CO2: critical dependence on imido N-substituents †

Catalytic Activity Dependency on Catalyst Components in Aerobic Copper–TEMPO Oxidation

“…Group 4 imido complexes24, 25 have attracted considerable attention26–42 for the past decade, in part because the MNR imido moiety exhibits substantial reactivity toward a wide range of unsaturated organic substrates such as alkynes, imines, and certain alkenes. These reactions typically proceed through formal [2 + 2] cycloadditions; however, nonterminal imido complexes such as vinylimido titanocenes undergo [4 + 2] cycloadditions with ketones, nitriles, and imines 43, 44.…”

Di-μ-chlorido-bis[dichlorido(N,N-diethylacetamidinato)(N,N-diethylacetamidine)titanium(IV)] acetonitrile disolvate

“…This can be attributed to electrostatic repulsion caused by substantial pi-electron donation from the diethylacetamidino nitrogen to the empty 3 d orbitals on Ti 4+ . The approximately linear Ti-N1-C1 bond angle (165.7 (2)°) and the short Ti-N1 bond length (1.751 (2) Å) indicate significant Ti-N1 multiple-bond character analogous to those observed in titanium(IV) imides (Guiducci et al, 2001;Lewkebandara et al, 1994;Dunn et al, 1994).…”

“…For the structure, see: Dunn et al (1994); Guiducci et al (2001); Lewkebandara et al (1994); Nielson et al (2001). For the reaction mechanism, see: Bradley & Ganorkar (1968); Chandra et al (1970); Forsberg et al (1987); Maresca et al (1986); Rouschias & Wilkinson (1968).…”

The Progression of Synthetic Strategies to Assemble Titanium Complexes Bearing the Terminal Imide Group

“…[3] Mountford and co-workers have commonly applied this strategy to assemble terminal aryl imide compounds of titanium. [16,17,21,[81][82][83][84] Likewise, Odom and co-workers have also used this tactic to prepare silyl imides. [85] However, this approach to incorporate the imide group relies on having an already assembled, highly donating (e.g., tBu), imido ligands.…”

“…[3][4][5][6][7] For example, this type of functionality is responsible for fundamentally important reactions such as the intermolecular activation of aliphatic (including methane) [8,9] as well as aromatic C À H bonds. [7,[10][11][12][13] The ubiquitous imide group can also participate in other processes such as cycloaddition reactions with substrates like carbon dioxide, [14][15][16][17][18][19][20][21] carbon disulfide, [14-16, 19, 22] ke-tones, [16,22,23] alkenes (intra-and intermolecularly), [24,25] A C H T U N G T R E N N U N G alkynes, [22,[24][25][26] nitriles, [23,27] isonitriles, [16,28] imines, [16,23,29,30] carbodiimides, [4,16,[30][31][32] allenes, [4,24,33] allylic alcohols, [34] and carboxamides…”