Sigmatropic rearrangements selection rules

Besides the selection rules, which are based on the conservation of orbital symmetry, for sigmatropic rearrangements of order [ij] it is possible to demonstrate that the following correlations will always apply ... 

The selection rules for sigmatropic rearrangements were deduced in this manner (Woodward R. B., Hoffmann R., /. Am. Chem. Soc., 1965, 87, 2511). 

The selection rules for sigmatropic rearrangements were derived for open-chain systems. A priori, it is not obvious that they also apply to cyclic systems. Using the PMO method, show that the following sigmatropic migrations21 are allowed ... 

The Woodward-Hoffmann selection rules for sigmatropic rearrangements are summarized in Table 8.2. 

Termmology of Cycloadditions Selection Rules for Cycloadditions Secondary Interactions Cycloadditions of Charged Species Sigmatropic Rearrangements Termmology... 

The generalized orbital symmetry selection rules are given below. The bases of these rules are discussed for each of the major classes of sigmatropic rearrangements. 

The rules in Table 29.1 are for determining whether a given electrocyclic reaction is allowed by orbital symmetry. There are also selection mles to determine whether cycloaddition reactions (Table 29.3) and sigmatropic rearrangements (Table 29.4) are... 

The selection rules that determine the outcome of electrocyclic reactions, cycloaddition reactions, and sigmatropic rearrangements are summarized in Tables 29.1, 29.3, and 29.4, respectively. This is still a lot to remember. Fortunately, the selection rules for all pericyclic reactions can be summarized in one word TE-AC. ... 

The selection rules for sigmatropic reactions are powerful predictors of thermal rearrangements. They explain how some reactions can occur ster-eospecifically and with surprisingly low activation energies, while others do not. For example, cfs-l,2-divinylcyclopropane (44) undergoes a [3,3] sigmatropic rearrangement to cis,cis-l,4-cycloheptatriene (45) with a half-life of... 

Analysis of these sigmatropic processes using Woodward-Hoffmann rules leads to selection rules for sigmatropic rearrangements (Table 4.1) [1, 2]. For sigmatropic rearrangements of order [i, j], where i > 1, the suprafacial or antarafacial nature of migration for both the components should be specified. 

Fig. 6.6. Thermal [1, 3]-sigmatropic shift with inversion at migratory centre. Selection Rule for Sigmatropic Rearrangement (FMO Method) ...

Selection rule for sigmatropic rearrangement of the order [1, /] (PMO-method)... 

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