Starting materials influencing transition structure

The familiar explanation for this example of site selectivity is that reaction at the 9,10-position creates two isolated benzene rings, whereas reaction at the 1,4-position would create a naphthalene nucleus, which is a less stable arrangement of two benzene rings. This explanation relies on the influence of product-like character in the transition structure, but we may also note that the same product is accounted for by looking at the frontier orbital coefficients of the starting materials the largest coefficients in the HOMO of 6.287 are at the 9,10-positions (see p. 174). 

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