Figure 2.

(A) Energy profiles of a desymmetrization reaction, where both potentially reacting alcohols are chemically equivalent. A catalyst that can selectively lower the activation barrier ( pathway, ) will result in high enantioselectivities,⁴ (B) Energy profiles of a site-selective transformation, where reactive groups are nonequivalent. Depending on the inherent energy profiles of the functional groups ( versus pathways, ), catalytic reduction of an energy barrier may not result in high observed selectivities ( pathway, ). The achievement of highly selective functionalizations may require substantially more selective catalysts ( pathway, ). (C) This problem is compounded by the addition of more reactive groups and (D) the ability for substrates to undergo multiple derivatization events.