Photochemistry as a Green Synthetic Method

Abstract

The photon is the green reagent par excellence. It is absorbed leaving no residue and induces deep-seated chemical transformations under mild conditions. Reactions via electronic excited states often reach the target via a shorter path than thermal alternatives, with excellent atom economy. Photochemistry also offers a way for the mild generation of highly reactive intermediates such as radicals or ions. This is illustrated by the example of arylation reactions via photo S N 1 process, a method that under some aspects rivals Pd-catalyzed reactions.