Palladium-Catalyzed Coupling of Naphthoquinone Triflates with Stannanes. Unprecedented Nucleophilic Aromatic Substitution on a Hydroxynaphthoquinone Triflate

Synthesis of 9Z-9-substituted retinoic acids by palladium catalyzed coupling reaction of a vinyl triflate with alkenyl stannanes.

Palladium catalyzed cross coupling reactions of a vinyl triflate intermediate and various alkenyl stannanes afforded trisubstituted Z-olefins stereoselectively in high yields. These olefins were then converted to the corresponding 9Z-retinoic acids via Horner-Emmons reaction and subsequent basic hydrolysis in excellent yields.

Modern Nucleophilic Aromatic Substitution

Pyridine sulfinates as general nucleophilic coupling partners in palladium-catalyzed cross-coupling reactions with aryl halides.

Pyridine rings are ubiquitous in drug molecules; however, the pre-eminent reaction used to form carbon-carbon bonds in the pharmaceutical industry, the Suzuki-Miyaura cross-coupling reaction, often fails when applied to these structures. This phenomenon is most pronounced in 2-substituted pyridines, and results from the difficulty in preparing, the poor stability of, and low efficiency in react...

A general palladium-catalyzed coupling of aryl bromides/triflates and thiols.

We have developed an efficient palladium-catalyzed carbon-sulfur bond formation reaction of aryl bromides, triflates, and activated aryl chloride. Using this protocol, we have shown tolerance to a wide variety of aryl thiols and alkyl thiols that can also be used as sulfide equivalents. [reaction: see text]

A QM/MM study of a nucleophilic aromatic substitution reaction catalyzed by 4-chlorobenzoyl-CoA dehalogenase.

Calculated using a QM/MM method, the free energy profile for the conversion of 4-chlorobenzoate to 4-hydroxybenzoate catalyzed by 4-chlorobenzoyl-CoA dehalogenase indicates the existence of a stable Meisenheimer complex.