Rhodium-catalyzed ortho-alkylation of aromatic aldimines and ketimines via CH bond activation

Rhodium-Catalyzed C−C Bond Formation via Heteroatom-Directed C−H Bond Activation

“…For these substrates, Wilkinson’s catalyst was ineffective, but a more electron-donating catalyst system employing a Rh-precatalyst and tricyclohexylphosphine (PCy 3 ) provided ortho -alkylated aryl aldehydes 21 and 22 following acidic hydrolysis (Table 2). 19 Using this more active catalyst system, over-alkylation was generally observed, but could be avoided by introducing a substituent at the 3-position to sterically encumber one site (entry 6) or by blocking one of the ortho positions (entry 7). Electron-donating (entries 2 and 3) and withdrawing (entries 4 and 5) substituents were tolerated on the aryl aldimine, and isomerizable olefins were effective substrates, though olefin isomerization to an internal position resulted in decreased yields.…”

Toward Waste‐Free Production of Heck Products with a Catalytic Palladium System under Oxygen

“…To circumvent these problems, aromatic carboxylic acid anhydrides and esters have been used by de Vries and co-workers [2] and Gooßen et al, [3] respectively, as sources of the aryl component in the PdCl 2 -catalyzed sp 2 -sp 2 coupling. [4] These include the chelation-assisted alkylation of aromatic ketones mediated by Ru or Rh, [5][6] the hydroarylation of alkenes or alkynes with Ir or Pd, [7][8] and the arylation of an olefin with Rh, [9] Ru, [10] or Pd. [3] Although CO and H 2 O are the only by-products, these reactions still have the disadvantages that they require high temperatures (160 8C), two separate steps, and a minimum concentration of alkali-metal halides for moderate catalyst activity (maximum TON (total turnover number = moles of coupling product per mole of Pd) of 400-150).…”

“…[4] These include the chelation-assisted alkylation of aromatic ketones mediated by Ru or Rh, [5][6] the hydroarylation of alkenes or alkynes with Ir or Pd, [7][8] and the arylation of an olefin with Rh, [9] Ru, [10] or Pd. [4] These include the chelation-assisted alkylation of aromatic ketones mediated by Ru or Rh, [5][6] the hydroarylation of alkenes or alkynes with Ir or Pd, [7][8] and the arylation of an olefin with Rh, [9] Ru, [10] or Pd.…”

Catalytic Addition of C – H Bonds to C – C Multiple Bonds

“…A variety of aromatic imines derived from the corresponding aldehydes and ketones can be used for this reaction [64,65]. The combination of the catalyst and the substrate is important for attaining high efficiency.…”