Abstract: MATH/CHEM/COMP 2002, Dubrovnik, June 24-29, 2002

The reaction of azulenes with the triphenylmethyl cation revisited

Edward C.  Kirby

Resource use Institute, 14 Lower Oakfield, Pitlochry, Perthshire PH16 5DS, Scotland, UK

It  has  been  known  for  several  decades  that  triphenylmethyl  perchlorate  in  the  presence   of   an   excess    of    1-methylazulene    in   boiling   acetic   acid   exchanges   its   cation   for   1-(3-methylazulen-1-yl)methylene-3-methylazulenium,  rather  than  the  1-(azulen-1-yl)methylene-3-methylazulenium which would be easier to explain (and which is the analogous product from 1,4-dimethyl-7-isopropylazulene). This probably happens by azulenyl interchange, but such a rationalisation has never appeared wholly satisfactory. A brief study of the components by molecular mechanics and extended Hückel calculations is being made in an attempt to disentangle some of the possible steric and electronic influences.