928267-40-7Relevant academic research and scientific papers
Scope and mechanism of carbonyl carbon and α-carbon bond cleavage of ketones by Iridium(III) porphyrin complexes
Li, Bao Zhu,Fung, Hong Sang,Song, Xu,Chan, Kin Shing
, p. 1984 - 1990 (2011/05/06)
Chemoselective carbonyl carbon and α-carbon bond activation (CCA) of ketones (RCOR) was successfully achieved with various iridium(III) tetrakis-4-tolylporphyrinato complexes Ir(ttp)X (X = (BF4)(CO), Cl(CO), and Me) to give the corresponding Ir(ttp)COR (R = Ar, Me, or Et) and Ir(ttp)R (R = Me or Et) complexes. Ir(ttp)(BF4)(CO) exhibited the highest reactivity toward CCA, as it possesses a higher Lewis acidity in catalyzing the aldol condensation of ketones to give water, which hydrolyzes the kinetic products, C-H bond activation (CHA) complexes, into the proposed Ir(ttp)OH for a subsequent CCA process. The CCA step is nonregioselective in giving both Ir(ttp)R and Ir(ttp)COR. However, Ir(ttp)R was kinetically less stable toward hydrolysis to give Ir(ttp)OH. Thus, only Ir(ttp)COR was observed as the sole CCA product.
Cleavage of carbonyl carbon and α-carbon bond of acetophenones by iridium(III) porphyrin complexes
Li, Bao Zhu,Song, Xu,Fung, Hong Sang,Chan, Kin Shing
scheme or table, p. 2001 - 2003 (2010/06/18)
Selective carbonyl carbon (C( - O)) and α-carbon (C(methyl)) bond activation of acetophenones was discovered by the high-valent, iridium(III) 5,10,15,20-tetrakis-4-tolylporphyrinato carbonyl chloride (Ir(ttp)Cl(CO)), which also acted as a Lewis acid in catalyzing the aldol condensation of acetophenones together with release of the coproduct water. Preliminary mechanistic studies suggest that both aliphatic and aromatic carbon-hydrogen bond activation products are kinetic products, which can be converted by reaction with water to iridium porphyrin hydride (Ir(ttp)H) via iridium porphyrin hydroxide (Ir(ttp)OH). Both Ir(ttp)OH and Ir(ttp)H were the possible intermediates to cleave the C( - O)-C(methyl) bond of acetophenones and to generate iridium porphyrin acyl complexes as the thermodynamic products.
Syntheses of acyliridium porphyrins by aldehydic carbon-hydrogen bond activation with iridium(III) porphyrin chloride and methyl
Song, Xu,Chan, Kin Shing
, p. 965 - 970 (2008/10/09)
Acyliridium porphyrins were synthesized by the reactions of aryl aldehydes with iridium(III) porphyrin chloride and methyl under solvent-free conditions with high yields. Selective aldehydic carbon hydrogen bond activation (CHA) was observed without any aromatic CHA in all the cases. Mechanistic investigation on the reactions with Ir(ttp)Cl(CO) suggested that (ttp)Ir cation was a likely intermediate of aldehydic CHA, whereas the CHA with Ir(ttp)Me underwent an oxidative addition or σ bond metathesis pathway. These reactions provided a facile synthesis of (arylacyl)iridium porphyrins.
