Tautomeric ligand enables biomimetic C—H hydroxylation with molecular oxygen

A process for making a compound of formula (2):

• which comprises contacting a compound of formula (1):
• with a source of Pd(II) in the presence of O2 and a ligand selected from the group consisting of:
• L26
• L27
• L28
• L29
• L30
• L31
• L32
• L33
• L34
• L35
• L36
• L37
• L38
• L39
• L40
• L41
• L42
• L43
• L44
• L45
• in a solvent under conditions sufficient to provide the compound of formula (2), wherein:
• Ar is selected from the group consisting of:
• wherein
• each ring in Ar is independently and optionally substituted with one to four substituents selected from the group consisting of —CN, halo, oxo, NRARB, C1-C6-alkyl, C1-C6-haloalkyl, C2-C6-alkenyl, C2-C6-alkynyl, C1-C6-alkoxy, C1-C6-haloalkoxy, —C(O)H, C(O)C1-C6-alkyl, C(O)NRARB, S(O)NRARB, S(O)2NRARB, C3-C14-cycloalkyl, C6-C10-aryl, C6-C10-aryloxy, 3- to 14-membered heterocycloalkyl and —(C1-C6-alkyl)-(3-to 14-membered heterocycloalkyl) (wherein 1-4 ring members are independently selected from N, O, and S), and 5-to 10-membered heteroaryl (wherein 1-4 heteroaryl members are independently selected from N, O, and S), wherein
• each alkyl, aryl, cycloalkyl, heterocycloalkyl, and heteroaryl moiety is optionally substituted with one to four substituents selected from the group consisting of halo, oxo, C1-C6-alkyl, C1-C6-haloalkyl, C1-C6-alkoxy, C(O)NRARB, C1-C6-alkoxy, C6-C10-aryl (optionally substituted by one to three halo and C1-C6-alkyl), and 5- to 10-membered heteroaryl (wherein 1-4 heteroaryl members are independently selected from N, O, and S;
• optionally substituted by one to three substituents selected from C1-C6-alkyl and 5- to 10-membered heteroaryl);
• and
• RA and RB are independently selected from the group consisting of H, C1-C6-alkyl, C1-C6-haloalkyl, —C1-C6-alkyl-C6-C10-aryl, C(O)C1-C6-alkyl, C(O)C1-C6-alkyl-C6-C10-aryl, C(O)OC1-C6-alkyl, C6-C10-aryl (optionally fused to C3-C14-cycloalkyl that is optionally substituted by one to four halo and C1-C6-alkyl), wherein
• each aryl is optionally substituted with one to three substituents selected from C1-C6-alkyl, halo, hydroxy, C1-C6-haloalkyl, and 3- to 14-membered heterocycloalkyl (wherein 1-4 ring members are independently selected from N, O, and S);
• each alkyl is optionally substituted with one to three substituents selected from halo, NRR′ (wherein R and R′ are independently selected from H, C1-C6-alkyl, C(O)C1-C6-alkyl, and C(O)C6-C10-aryl).