Woodward-Hoffmann rules generalised rule

Such an alternative reproduction of the Woodward-Hoffmann rules is not, however, the only result of the similarity approach. The formalism of the approach is very flexible and universal and the original study [33] has become the basis of a number of subsequent generalisations in which a number of problems dealing with various aspects of pericyclic reactivity were analysed and discussed [48-55], In spite of the considerably broad scope of these applications, recently reviewed in [56], the possibilities of the similarity approach are still not exhausted and its formalism is still capable of further methodological development. Our aim in this report is to present some of more recent applications of the similarity approach for the study of mechanisms of pericyclic reactions [57-59],... 

The combination of Hiickel and Mobius generalisations can be utilised to restate the Woodward-Hoffmann rules [31], in a manner that has been popularised by Zunmermann... 

Between 1965 and 1969 Woodward and Hoffmann presented rules for each of the different classes of pericyclic reaction. They showed that the allowedness or otherwise of reactions depended critically upon their stereochemistry. We shall go through the rules twice first the rules class-by-class, and then again using the generalised mle that applies to all classes of pericyclic reactions. 

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