Putting corannulene in its place. Reactivity studies comparing corannulene with other aromatic hydrocarbons

Abstract

A series of aromatic hydrocarbons were investigated so as to compare the reactivity of corannulene with planar aromatic hydrocarbons. Corannulene was found to be more reactive than benzene, naphthalene and triphenylene to Friedel-Crafts acylation whilst electrophilic aromatic bromination was also used to confirm that triphenylene was less reactive than corannulene and that pyrene, perylene and acenaphthene were more so. The stabilisation of a neighbouring carbocation by the various aromatic systems was investigated through consideration of the rates of methanolysis of a series of benzylic alcohols. The reactivity series was found to parallel that observed for the electrophilic aromatic substitutions and both series are supported by computational studies. As such, a reactivity scale was devised that showed that corannulene was less reactive than would be expected for an aromatic planar species of similar pi electron count.

Electronic effects on the substitution reactions of benzhydrols and fluorenyl alcohols. Determination of mechanism and effects of antiaromaticity

“…With the necessary species in hand, kinetic experiments were carried out to determine the observed first order rate constant (k obs ) for the methanolysis of the benzhydrols 7. ‡ Determined in a manner analogous to described previously using 1 H NMR spectroscopy, 33 the observed rate constant is a function of the extent of protonation of the alcohol and the acid concentration. As also detailed previously, variation in the former can be considered negligible and all changes in the observed rate constant attributed to changes in the substrate affecting the stabilisation of the intermediate carbocation.…”

High performance microwave absorption of light weight and porous non-carbon-based polymeric monoliths via a gel emulsion template

“…The ferrocene derivative was synthesized by the Friedel-Crafts acylation reaction and Wittig reaction. 88,89 The molecular structure of the compound 2DPrEnF was confirmed by 1 H NMR and 13 C NMR spectroscopy and high-resolution MS.…”

Synthesis of pharmaceutical drugs from cardanol derived from cashew nut shell liquid

“…Norfenefrine can be synthesised in 5 steps from benzene (Scheme 12). Acetophenone synthesised from the benzene by a Friedel-Crafts reaction, 46 was reacted with bromine fluoride to form the 1-(3-bromophenyl)ethan-1-one. 47 The bromide was converted to 1-(3-hydroxyphenyl)ethan-1-one by using a Pd/ t BuPhos system.…”

“…The synthesis of etilefrine can be achieved starting from benzene, 1-(3-hydroxyphenyl)ethan-1-one is obtained using the same initial pathway to the synthesis of norfenefrine. [46][47][48] 1-(3-Hydroxyphenyl)ethan-1-one was then converted to 3-acetylphenyl acetate using magnesium perchlorate as catalyst, 55 and a bromination of 3-acetylphenyl acetate afforded 3-(2-bromoacetyl)phenyl acetate, 56 which was then converted to the etilefrine with ethylamine, sodium borohydride and water (Scheme 14). 57 The atom efficiency of this fossil fuel based synthetic method is 28%, which is slightly higher than our synthetic method starting from cashew nut shell liquid, 22%.…”