For example, the pioneer work by MacMillan of the direct decarboxylative of carboxylic acids for radical Michael additions, through alkyl radical I, has been accomplished via visible light-mediated photoredox catalysis (Figure ). Later on, in 2018, Zhu and Xie have developed the straight deoxygenative ketone synthesis from readily available aromatic carboxylic acids and alkenes, via acyl-radical II (Figure ). In this approach, the visible-light photoredox catalysis enables the direct deoxygenation of acids as acyl sources with triphenylphosphine and represents a distinct perspective on activation (Figure ).