Figure 2.
3–21G-calculated manzamine-derived allylic carbonium ion 3a showing a pretransition state transannular H-34 to C-10 distance of 3.43 Å. Of interest, the H-34 to C-10 distance in Figure 1 (manzamine A, 3) is 5.14 Å, the shortened distance arising as a result of conformational transmission.