Nonradical Trapping Pathway for Reactions of Nitroxides with Rhodium Porphyrin Alkyls Bearing β-Hydrogens and Subsequent Carbon−Carbon Bond Activation
摘要:
A novel nitroxide-induced hydrogen atom abstraction and beta-elimination of rhodium porphyrin alkyls has been observed. Subsequent carbon-carbon bond activation of methyl-substituted nitroxides by the rhodium(II) porphyrin radical yielded rhodium porphyrin methyl complexes.
Alkylation of Rhodium Porphyrin Complexes with Primary Alcohols under Basic Conditions
作者:Yongjun Bian、Chun Meng Tam、Ching Tat To、Xingyu Qu、Kin Shing Chan
DOI:10.1021/acs.organomet.9b00454
日期:2019.10.14
utilized as the alkylating reagents to conveniently access rhodium porphyrin alkyl complexes in up to 91% yields under basic conditions. Mechanistic investigations suggest two possible pathways for the C–O bond cleavage: (1) nucleophilic substitution with rhodium(I) porphyrin anion and (2) a borrowing hydrogen pathway via rhodium(III) porphyrin hydride.
Nitroxide-induced beta-hydrogen atom abstraction and beta-elimination of rhodium porphyrin alkyls have been observed. Rhodium(II) porphyrin radical were proposed intermediates to form first and subsequently reacted via aliphatic carbon–carbon bond activation with alkyl substituted nitroxides to yield rhodium porphyrin alkyl complexes.
Acylation of Rhodium(III) Porphyrin Complexes with Carboxylic Acids: Scope and Mechanism
作者:Ho Yin Yu、Hung Kay Lee、Kin Shing Chan
DOI:10.1021/acs.organomet.1c00457
日期:2021.11.22
Rhodium(III) porphyrin complexes undergo C(═O)–O bond activation (COA) of carboxylic acids to give the corresponding rhodium(III) porphyrin acyl complexes RhIII(ttp)COR up to 90% yield. Mechanistic studies suggested either a σ-bond metathesis reaction or 1,2-addition between an active rhodium(III) porphyrin hydride species, RhIII(ttp)–H, and the carboxylic acid (R(C═O)–OH) to give the corresponding
铑 (III) 卟啉配合物经过羧酸的 C(=O)-O 键活化 (COA),得到相应的铑 (III) 卟啉酰基配合物 Rh III (ttp)COR,产率高达 90%。机理研究表明活性铑 (III) 卟啉氢化物 Rh III (ttp)-H 和羧酸 (R(C=O)-OH)之间的 σ 键复分解反应或 1,2-加成反应给出相应的 Rh III (ttp)COR 产物。