Regioselectivity in the Real I Ions of Methoxy Dehydrobenzfnes with Furans

I make no excuse for delivering today, (at a conference devoted to natural products chemistry), a lecture which has a distinct physical organic flavour. In the past the study of the chemistry of natural products presented ample opportunities for the development and testing of the principles by which organic molecules undergo reactions. The advent of spectroscopic techniques and the X-ray method has now liberated the organic chemist from the burden of structural determination by classical methods of degradation so that new developments in chemical theory must now often arise from the endeavours of the synthetic chemist whose goals are complex biologically active natural products. A pertinent example of such an advance in chemical theory is the propounding of the Woodward-Hoffmann rules on the conservation of orbital symmetry in cyclisation reactions. 1