Photoredox catalysis approach

MacMillan described a photoredox catalysis approach whereby photo-excited ruthenium(ii) species generate a trifluoromethyl radical which is then trapped by a silylenolether (Scheme 15.106). The reaction displays broad utility in terms of applicable substrates and extends to enol silanes of ketones, esters or amides. °... 

Nicewicz and MacMillan merged later photoredox catalysis and asymmetric organocatalysis to an efficient approach to the otherwise difficult asymmetric a-alkylation of aldehydes 118 by activated alkyl bromides 117 (Fig. 30) [183]. The concept of face differentiation at the a-position of aldehydes via chiral enamines 121 provides the basis for the method. This allows the formation of functionalized... 

Although the results of the last two approaches below previously reported results, this new extension of organo-photoredox catalysis to classic organic dyes would find broadly utility across many applications. 

---