“…In addition, the allylic coupling involving the more axial proton at C-4 (i.e., J2,4' in 2a, 5, and 7; J2,4 in 6) changes very little, which is quite consistent with theoretical predictions from INDO calculations. 18 The allylic coupling involving the more equatorial proton (J 1,3 and J2,4 in 2a, 4, and 5; J2,4-in 6, and 72-4 in 7) is predicted18 to be more sensitive to conformational charges, but, unfortunately, is too small to be useful (or, in several cases, to be measured).…”