872415-72-0Relevant academic research and scientific papers
Base-Promoted C-O Bond Cleavage of Primary Alcohols by Iridium(III) Porphyrin Chloride
Bian, Yongjun,Qu, Xingyu,Chan, Kin Shing
, p. 1376 - 1383 (2020)
Various Ir(por)-benzyls and Ir(por)-alkyls (por = porphyrinato dianion ligand) were successfully synthesized with benzyl and 1° alkyl alcohols by C-O bond cleavage with Ir(ttp)(CO)Cl (ttp = 5,10,15,20-tetraphenylporphyrinato dianion) in alkaline media. The alkylation products were afforded in up to 92% yields. Mechanistic investigations suggest that both the Ir(ttp)- anion and Ir(ttp)H are key intermediates via a hydrogen-borrowing pathway.
Alkyl Carbon-Oxygen Bond Cleavage of Aryl Alkyl Ethers by Iridium-Porphyrin and Rhodium-Porphyrin Complexes in Alkaline Media
Chen, Chen,Chan, Kin Shing
, p. 3456 - 3464 (2017/10/03)
Alkyl C-O bond cleavage in aryl alkyl ethers was achieved with Rh(ttp)Cl (1a; ttp = 5,10,15,20-tetrakis(p-tolyl)porphyrinato dianion) together with competitive alkyl C-H bond activation in alkaline media. In contrast, selective alkyl C-O bond cleavage occurred with the iridium-porphyrin Ir(ttp)(CO)Cl (1b)/KOH. Mechanistic investigations indicate the coexistence of MI(ttp)- and M2II(ttp)2 (M = Rh, Ir) under basic conditions. With a weaker Rh(ttp)-Rh(ttp) bond, RhII(ttp)· metalloradical exists in an appreciable amount to cleave the alkyl C-H bond, competing with the alkyl C-O bond cleavage via RhI(ttp)-. In contrast, the more nucleophilic IrI(ttp)- cleaves the alkyl C-O bond exclusively.
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.
