A highly efficient, convergent approach to the synthesis of the angiotensin I1 receptor antagonist losartan (1) is described. Directed ortho-metalation of 2-trityl-5-phenyltetrazole provides the key boronic acid intermediate 10 for palladium-catalyzed biaryl coupling with bromide 5 obtained from the regioselective alkylation of the chloroimidazole 2. This methodology overcomes many of the drawbacks associated with previously reported syntheses.

The palladium-catalyzed coupling of aryl and heteroaryl chlorides with primary amides under mild homogeneous reaction conditions is reported. Successful C−N coupling is enabled by the use of a unique "dual-base" system consisting of DBU and NaTFA, which serve as proton acceptor and halide scavenger, respectively, using low catalyst loadings (0.5 mol %) with readily available, air-stable palladium precatalysts. The DBU/NaTFA system also enables the room-temperature coupling of primary aryl amines with aryl chlorides and is tolerant of a variety of base-sensitive functional groups.

A practical synthesis of nicotinamide mononucleotide (b-NMN) and a high yield coupling with AMP-morpholidate that also provides NAD + in an efficient manner are reported.

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Investigations into nickel-catalyzed borylation reactions have led to the development of an experimental design of 24 reaction conditions for rapid lead identification. A case study on the borylation of a model aryl bromide with B 2 (OH) 4 prompted a series of mechanistic and stability studies to better understand the catalytic cycle and factors that affect robustness. HTEx was employed to study the effect of a series of scavengers on the remediation of nickel from the reaction stream. These combined results have generated an increased understanding of nickel-catalyzed borylation reactions and set the stage for their expanded use in process chemistry.

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4-Cyanobenzenesulfonamides of secondary amines were found to cleave to the parent amine cleanly under the action of thiol and base. This feature readily lends itself to the use of this motif as an amine protecting/activating group within a broader context of amine synthesis. The crystalline sulfonamides could be further elaborated by alkylation and arylation similarly to nitrobenzenesulfonamides. The sulfonamides could withstand conditions that functionalize nitroarenes, such as reductions and vicarious nucleophilic substitution reactions.

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