1,5-Methano annulene carboxylic acid

On attempted aerial oxidation of 1,5-methano [10]annulene carboxylic acid anilide 351 (Scheme 118) Sho Ito and co-workers [150] obtained the prod-... 

Various substituted l,6-methano-[10]annulenes have been prepared and characterized, and in particular the n.m.r. of such compounds reflects their delocalized nature 17,120,124-127) (a 71-complex formed from reaction of l,6-methano-[10]annulene with hexacarbonylchromium has also been characterized 128>). The X-ray crystallographic analysis 129> of the 2-carboxylic acid derivative 24 shows the bridge angle to be 99.6 °, and thus that the Cio perimeter is even flatter than expected from molecular models. Furthermore, the ten perimeter bonds have lengths which vary over the narrow range 1.38 to 1.42 A, the values being typical of benzenoid aromatic bonds. This lack of appreciable... 

Methano[10]annulene is aaetylated, at the 2-position, by acetic anhydride in the presence of tin(IV) chloride [106,142]. The acetyl group has been converted into a carboxylic acid group by the action of sodium hypobromite [142],... 

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