Methods for practical synthesis of deuterated amino acids

A method for preparing a deuterated compound of formula (I), or a salt thereof,

• wherein
• R1 is alkyl, —C(O)alkyl, alkenyl, —C(O)alkyenyl, cycloalkyl, —C(O)cycloalkyl, cycloalkenyl, —C(O)cycloalkenyl, aryl, —C(O)aryl, heteroaryl, —C(O)heteroaryl, heterocyclyl, or —C(O)heterocyclyl, wherein R1 is optionally substituted with one or more Ra;
• R2 is H or an amino protecting group;
• R3 is —CRbRcRd;
• Ra at each occurrence is independently halogen, —CN, —OH, nitro, a protected hydroxyl, a protected amino, 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;
• Rb, Rc, and Rd are independently H, alkyl, or Rb and Rc together with the carbon they are attached to form a ring;
• the method comprising:
• (i) mixing R1—COOD with a compound of formula (II), a base, and a photocatalyst in an essentially H2O free solvent comprising D2O and an organic solvent to form a mixture;
• and
• (ii) exposing the mixture of (i) to light, thereby producing the deuterated compound of formula (I), or a salt thereof.