Corannulenes annelated

The reduction of several annelated corannulene derivatives has been performed using lithium and potassium metals.7 It has been found that annelation affects the annulenic character of corannulene by changing its charge distribution the dianions of derivatives that are annelated with six-membered rings have less annulenic character and are less paratropic than corannulene dianion. 

It has been shown by B3LYP/6-31IG" calculations that the characteristic bowl shape of corannulene 6 is flattened in the corresponding fully furo[r]-annelated derivative 7, which thus is by and large analogous to the decamethylidene derivative 8 <2004JOC8111>. 

Numerous aromatic compounds including several bowl-shaped fullerene fragments have been prepared by this method, e.g. cyclopenta[z/]fluoranthene (22, Scheme8, [54d,56a]), cyclopenta[bc]corannulene (23, [55a]) and diace-naphtho[3,2,l,8-cdejg 3, 2, l, 8 -Zmnop]chrysene (24, see Scheme 9, [55b,c]). Of special importance is this approach for the synthesis of cyclopenta-annelated PAHs, e.g. and the three isomeric dicyclopentapyrenes (25-27, Scheme 9, [54e, 56b]). Using these reference samples, several cyclopenta-annelated PAHs could be identified as byproducts formed in the incomplete oxidation of hydrocarbons in fuel rich flames [57]. 

Various (heterocyclic) six-membered pcn-annelated corannulenes 70-74 were accessed by the reaction of divalent nucleophiles with 2,3-bis(bromomethyl)-... 

Table 5 The inversion barrier (kcal/mol) and the bowl depth (A) of pen-annelated corannulenes...

Dinadayalane, T. G., Deepa, S., Sastry, G. N. (2003). Is peri hydrogen repulsion responsible for flattening buckybowls The effect of ring annelation to the rim of corannulene. Tetrahedron Letters, 44, 4527-4529. 

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