Iridium-Catalyzed [3 + 2] Annulation of 1,3-Dienes with ortho-Carbonylated Phenylboronic Acids. A Catalytic Process Involving Regioselective 1,2-Addition

Formation of 5-membered metallacycles at iPrPCPIr by C–H, O–H, and C–CO bond cleavage

“…the C3-C2 and C1-O1 bonds are longer, and C2-C1 bond shorter, than those reported for free benzophenone [45]. Though the differences are somewhat small (1.43, 1.26, and 1.45 Å, versus 1.40, 1.23, and 1.48 Å, respectively), they are consistent with the expected lengthening/shortening pattern in the event of resonance between iridium and the benzophenone ligand (Scheme 7) and are comparable to the differences observed between the related tBu PCPIr ethyl vinyl ketone adduct [29] and a reported a,b-enone [46] where resonance has been suggested. Based on these data it is likely that proposed resonance form II contributes at least somewhat to the molecular structure of 3b.…”

Harnessing C–H Borylation/Deborylation for Selective Deuteration, Synthesis of Boronate Esters, and Late Stage Functionalization

“…This indicated that the starting material arose from protolytic deborylation. Moreover, given that Ir-catalyzed additions of aryl boron compounds are known, 27,28 and deborylations have been implicated under the conditions of Ir-catalyzed borylations, 19,29 the deborylations we observed in one-pot reactions were likely Ir-catalyzed.…”

Total Synthesis of (+)-Raputindole A: An Iridium-Catalyzed Cyclization Approach

“…Our total synthesis of raputindole A ( 1 ) aimed to avoid the use of an indoline as a surrogate of the indole ring because it would require additional steps, including a late-stage oxidation of an indoline intermediate. Instead, our strategy features the use of N -tosyl indoles in both the northern and southern parts of the structure, an iridium-catalyzed diastereoselective cyclization, 14 a methallylation reaction to install the isobutenyl side chain at C-7, and a Heck cross-coupling reaction to build the raputindole A ( 1 ) scaffold. It is noteworthy that our approach incorporates an enzymatic resolution step that allows us to obtain (+)-raputindole A ( 1 ).…”