93898-92-1Relevant academic research and scientific papers
Rhodium-Catalyzed meta-Selective C?H Carboxylation Reaction of 1,1-Diarylethylenes via Hydrorhodation-Rhodium Migration
Caner, Joaquim,Iwasawa, Nobuharu,Saito, Takanobu,Toriumi, Naoyuki
supporting information, p. 23349 - 23356 (2021/09/18)
A meta-selective C?H carboxylation reaction of 1,1-diarylethylene derivatives with CO2 by using a rhodium catalyst with NaOiPr as a stoichiometric reductant has been achieved. Together with hydrogenation of the ethylene moiety, a carboxyl group was introduced to the meta-position of the aryl ring with high selectivity over the ortho-positions. Experimental and computational mechanistic studies indicate that this carboxylation reaction proceeds via hydrorhodation on the ethylene moiety, followed by 1,4-rhodium migration and successive 1,2-rhodium migration on the aryl ring. The use of a bulky phosphine ligand seems to be the key to this unusual aryl-to-aryl 1,2-rhodium shift.
Scalable Electrochemical Dehydrogenative Lactonization of C(sp2/sp3)-H Bonds
Zhang, Sheng,Li, Lijun,Wang, Huiqiao,Li, Qian,Liu, Wenmin,Xu, Kun,Zeng, Chengchu
supporting information, p. 252 - 255 (2018/01/17)
A practical, electrochemical method is developed for the direct dehydrogenative lactonization of C(sp2/sp3)-H bonds under external oxidant- and metal-free conditions, delivering diverse lactones, including coumarin derivatives with excellent regioselectivity. The scalable nature of this newly developed electrochemical process was demonstrated on a 40 g scale following an operationally simple protocol. The remote lactonization of C(sp3)-H bonds would constitute an important synthetic advance toward electrochemical C-O bond formation.
Stereoelectronic effects in the deprotonation of arylalkyl radical cations: meso-ethylanthracenes
Tolbert, Laren M.,Khanna, Rajive K.,Popp, Ann E.,Gelbaum, Leslie,Bottomley, Lawrence A.
, p. 2373 - 2378 (2007/10/02)
In contrast to meso-methylanthracenes, which are oxidized by one-electron oxidants to hydroxymethyl derivatives, meso-ethylanthracenes such as 9,10-diethylanthracene (DEA) undergo a facile chemical or biochemical oxidative elimination of ethylene to yield an anthrone. No trace of ethyl side chain oxidation to a 1-hydroxyethyl derivative is observed. The rationale for this dramatic selection between methyl and ethyl reactivity is a stereoelectronic effect on radical cation deprotonation. 9-Ethyl-10-methylanthracene (EMA) undergoes both oxidative pathways, but the competition between the two pathways is mediated by water. This effect is attributed to the intervention of a water cluster in the deprotonation reaction.
