18153-43-0Relevant articles and documents
Experimental Evidence for p Ka-Driven Asynchronicity in C-H Activation by a Terminal Co(III)-Oxo Complex
Goetz, McKenna K.,Anderson, John S.
, p. 4051 - 4062 (2019/03/07)
C-H activation by transition metal oxo complexes is a fundamental reaction in oxidative chemistry carried out by both biological and synthetic systems. This centrality has motivated efforts to understand the patterns and mechanisms of such reactivity. We have therefore thoroughly examined the C-H activation reactivity of the recently synthesized and characterized late transition metal oxo complex PhB (tBuIm)3CoIIIO. Precise values for the pKa and BDFEO-H of the conjugates of this complex have been experimentally determined and provide insight into the observed reactivity. The activation parameters for the reaction between this complex and 9,10-dihydroanthracene have also been measured and compared to previous literature examples. Evaluation of the rates of reaction of PhB(tBuIm)3CoIIIO with a variety of hydrogen atom donors demonstrates that the reactivity of this complex is dependent on the pKa of the substrate of interest rather than the BDEC-H. This observation runs counter to the commonly cited reactivity paradigm for many other transition metal oxo complexes. Experimental and computational analysis of C-H activation reactions by PhB(tBuIm)3CoIIIO reveals that the transition state for these processes contains significant proton transfer character. Nevertheless, additional experiments strongly suggest that the reaction does not occur via a stepwise process, leading to the conclusion that C-H activation by this CoIII-oxo complex proceeds by a pKa-driven "asynchronous" concerted mechanism. This result supports a new pattern of reactivity that may be applicable to other systems and could result in alternative selectivity for C-H activation reactions mediated by transition metal oxo complexes.
KHMDS mediated synthesis of 9-arylfluorenes from dibenzothiophene dioxides and arylacetonitriles by tandem SNAr-decyanation-based arylation
Mylavarapu, Saketh,Yadav, Mamta,Bhanuchandra
supporting information, p. 7815 - 7819 (2018/11/21)
A straightforward KHMDS mediated synthetic route to 9-arylfluorenes from readily available starting materials has been developed. This reaction involves SNAr reactions of dioxide with arylacetonitriles, followed by decyanation reaction. The pro
Direct C-H bond arylation of fluorenes with aryl chlorides catalyzed by N-heterocyclic carbene-palladium(ii)-1-methylimidazole complex and further transformation of the products in a one-pot procedure
Ji, Ya-Yun,Lu, Li-Li,Shi, Yu-Chun,Shao, Li-Xiong
, p. 8488 - 8498 (2014/12/10)
We report here the NHC-Pd(ii)-Im complex 1-catalyzed direct C-H bond functionalization of the C9 position of fluorenes with aryl chlorides and further transformation of the resulting products in a one-pot procedure. Under the optimal conditions, arylated fluorenes can be obtained in moderate to almost quantitative yields using various activated and unactivated (hetero)aryl chlorides as the arylating reagents. Furthermore, if the mixture from the arylation reaction is exposed to air, the C9-oxidized products can be obtained in acceptable to good yields in a one-pot procedure. In addition, alkyl groups can also be efficiently introduced to the above mixture from the arylation reaction, producing further C9-alkylated products in good to almost quantitative yields in a one-pot procedure, thus providing an expedient, inexpensive and practical strategy for the mono- and di-functionalization of fluorenes. This journal is
