Changing the Initial Orientation

The initial orientation of the reactants in Fig. 7.2 was chosen because the cis and trans forms of the product belong to its non-trivial subgroups, C and Cj respectively. However, the two orientations on the left and right sides of Fig. 7.3 are equally probable modes of approach and also have symmetry. 

At first sight. Approach (B) is only suitable for the [ 4a mode the 

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