A bridged two-vial system aminocarbonylation protocol where Mo(CO)(6) functions as an external in situ solid source of CO has been developed. For the first time both nitro group containing aryl/heteroaryl iodides and bromides gave good to excellent yields in the Mo(CO)(6)-mediated and palladium(0)-catalyzed conversion to benzamides, while the identical one-vessel protocol afforded extensive reduction of the nitro functionality. The above-mentioned bridged two-compartment protocol furnished good results with both primary amines and secondary amines and sluggish aniline nucleophiles at 65-85 °C reaction temperatures.

We describe the successful implementation of palladium-aryl oxidative addition complexes as stoichiometric reagents in carbonylation reactions with (11)CO to produce structurally challenging, pharmaceutically relevant compounds. This method enables the first (11)C-carbonyl labeling of an approved PET tracer, [(11)C]raclopride, for the dopamine D2/D3 receptor by carbonylation with excellent radiochemical purity and yield. Two other molecules, [(11)C]olaparib and [(11)C]JNJ 31020028, were efficiently labeled in this manner. The technique distinguishes itself from existing methods by the markedly improved purity profiles of the tracer molecules produced and provides access to complex structures in synthetically useful yields, hereby offering a viable alternative to other (11)C-labeling strategies.

A palladium-catalyzed CO gas-free carbonylative Sonogashira/cyclization sequence for the preparation of functionalized 4-quinolones from 2-iodoanilines and alkynes via two different protocols is described. The first method (A) yields the cyclized products after only 20 min of microwave (MW) heating at 120 °C. The second method (B) is a gas-free one-pot two-step sequence which runs at room temperature, allowing the use of sensitive substituents (e.g., nitro and bromide groups). For both protocols, molybdenum hexacarbonyl was used as a solid source of CO.

A mild and effective method is described for C-labeling of peptides selectively at the N-terminal nitrogen or at internal lysine positions. The presented method relies on the use of specific biphosphine palladium-methyl complexes and their high reactivity towards amino-carbonylation of amine groups in the presence [ C]carbon monoxide. The protocol facilitates the production of native N- C-acetylated peptides, without any structural modifications and has been applied to a selection of bioactive peptides.