Processes for isotopic modification of polyunsaturated fatty acids and derivatives thereof

A method for isotopic modification of a polyunsaturated lipid, comprising:

• reacting the polyunsaturated lipid with an isotope-containing agent in a presence of a transition metal catalyst to obtain an isotopically modified polyunsaturated lipid having an isotope at one or more bis-allylic positions, wherein the isotope-containing agent comprises at least one isotope selected from the group consisting of deuterium, tritium, and combinations thereof;
• and wherein the transition metal catalyst has a structure of Formula (I) or (II):
• [ML1(L2)m(L3)n]pQk (I)
• [ML1(L2)m1(L3)n1]-L-[ML1(L2)m2(L3)n2]qQk (II)
• wherein:
• M is rhodium, iridium, or ruthenium;
• each L1 is independently C3-C10 cycloalkenyl, C4-C10 cycloalkynyl, C6-C10 aryl, 5 to 10 membered heteroaryl, or 3 to 10 membered heterocyclyl, wherein L1 is optionally substituted with one or more RA;
• each L2 is independently imine, carbene, carbonyl, alkene, alkyne, nitrile, isonitrile, acetonitrile, ether, thioether, phosphine, pyridine, optionally substituted C3-C10 cycloalkenyl, optionally substituted C4-C10 cycloalkynyl, optionally substituted C6-C10 aryl, optionally substituted 5 to 10 membered heteroaryl, or optionally substituted 3 to 10 membered heterocyclyl;
• each L3 is independently C1-C6 alkyl, NR1R2 or C1-C6 alkoxy;
• each R1 and R2 is independently H, optionally substituted C1-C6 alkyl, optionally substituted C3-C10 cycloalkyl, optionally substituted C3-C10 cycloalkenyl, optionally substituted C4-C10 cycloalkynyl, optionally substituted C6-C10 aryl, optionally substituted 5 to 10 membered heteroaryl, or optionally substituted 3 to 10 membered heterocyclyl;
• each RA is independently hydroxyl, halogen, cyano, nitro, optionally substituted C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C1-C6 alkoxy, C1-C6 haloalkyl, C1-C6 haloalkoxy, or optionally substituted amino;
• L is C1-C6 alkylene, C2-C6 alkenylene or C2-C6 alkynylene linker;
• m, m1, m2, n, n1 and n2 are independently an integer of 1, 2 or 3;
• p and q are independently an integer of 1, 2, 3 or 4;
• Q is an anion;
• and
• k is 0, 1 or 2.