Formation and Cleavage of C−H, C−C, and C−O Bonds of ortho-Methyl-Substituted Anisoles by Late Transition Metals

Abstract

2,6-Dimethyl-substituted anisoles can be converted into the corresponding 2-ethyl-6-methylphenols in a several-step reaction mediated by a TpMe2Ir(III) complex; use of the 13C-enriched anisoles, ArO13CH3, shows that the 13C label distributes across the two ethyl sites with a preference for the terminal position.

Synthetic, Mechanistic, and Theoretical Studies on the Generation of Iridium Hydride Alkylidene and Iridium Hydride Alkene Isomers

“…A detailed theoretical study of this complex rearrangement is outside the scope of this work, but it is tempting to suggest that species C , resulting from a 1,2‐H shift from iridium to the alkylidene ligand of B , could equilibrate partially with a cyclohexadienone intermediate, D (Scheme ), prior to experiencing an irreversible α‐aryloxide elimination, subsequent CC coupling involving the resulting methylene unit, and β‐H elimination (see Scheme in ref. 11b). It should be noted that species of type D are organometallic cyclohexadienones.…”

Palladium‐Catalyzed Selective Carbofunctionalization of Inert γ‐C(sp3)−O Bonds with 4‐Hydroxypyridin‐2(1H)‐ones and 4‐Hydroxy‐2H‐pyran‐2‐ones

“…[3] Significant progress has been made in realizing the activation of aryl, benzyl, and allyl CÀ O bonds through the strategy of oxidative addition of low-cost metals to CÀ O bonds. [4,5] However, several limitations exist in the above reactions such as the narrow substrate scope, the use of stoichiometric metal catalysts or organometallic reagents and poor selectivity. Therefore, the development of new strategies to overcome these limitations and realize the functionalization of inert CÀ O bonds is highly desired.…”

Oxidative addition of ether O-methyl bonds at a Pt(0) centre

“…Activation of C-O bonds of ethers at transition metals, first described many years ago, [15][16][17] has been rejuvenated by the work of Carmona, Paneque 18,19 and Goldman 20,21 who investigated the reactivity of iridium tris(pyrazolyl)borate and iridium pincer complexes, respectively. In both cases, the C-O activation was associated with initial methyl C-H bond activation (see Scheme S1 in ESI ‡).…”