Visible-light mediated organophotoredox catalytic deuteration of aromatic and aliphatic aldehydes

A method for preparing a deuterated aldehyde of formula:

• RZ—C(O)-D
• wherein:
• RZ is alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, heteroaryl, or heterocyclyl;
• wherein the alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, heteroaryl, and heterocyclyl are each optionally substituted with one or more Ra, and RZ is optionally deuterated;
• Ra at each occurrence is independently halogen, —CN, —OH, nitro, —O-benzyl, —NH(t-butoxycarbonyl), —NH(benzyloxycarbonyl), or —X—RX, wherein X is bond, O, NH, C(O), OC(O), or C(O)NH;
• and RX is alkyl, alkenyl, alkynyl, alkoxy, cycloalkyl, aryl, heteroaryl, or heterocyclyl, wherein the RX is optionally substituted,
• the method comprising:
• (i) mixing an aldehyde of formula:
• RZ′—C(O)—H
• with a photocatalyst and a hydrogen atom transfer agent in a H2O free solvent comprising D2O and an organic solvent under an inert gas to form a mixture;
• wherein the photocatalyst is:
• or a salt thereof;
• wherein RZ′ is alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, heteroaryl, or heterocyclyl;
• wherein the alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, heteroaryl, and heterocyclyl are each optionally substituted with one or more Rb;
• Rb at each occurrence is independently halogen, —CN, —OH, nitro, —O-benzyl, —NH(t-butoxycarbonyl), —NH(benzyloxycarbonyl), or —Y—RY, wherein Y is bond, O, NH, C(O), OC(O), or C(O)NH;
• and RY is alkyl, alkenyl, alkynyl, alkoxy, cycloalkyl, aryl, heteroaryl, or heterocyclyl, wherein the RY is optionally substituted, and
• (ii) exposing the mixture of (i) to light, thereby producing the deuterated aldehyde.