Today in ChemRxiv we report an unusual and surprising organometallic rearrangement triggered by addition of Pd(TFA)₂ to at alkenyl benzothiazole thioether (BT(S)). This story started two years ago. While wrapping up an in-depth study of the BT(S) directing group and its various uses in palladium(II) catalysis (ACS Catal. 2019, 9, 7626), Andrew treated a standard substrate with Pd(TFA)₂. Rather than forming the PdX₂(substrate)₂ complex like we was with other Pd(II) salts, Andrew obtained an unusual structure where the organic ligand had undergone significant rearrangement and was now coordinated as a bidentate N,S-heterocyclic-carbene–tetrahydrothiophene—shout out to UCSD Crystallography for elucidating the structure! Andrew then teamed up with a high school intern, Matt Demer (now at UC Davis), and continued close collaboration with crystallographers Milan and Arnie from UCSD to understand the scope, limitations, and mechanism of this process. Bravo, Andrew and team!

For a link to the pre-print, click here: https://chemrxiv.org/articles/preprint/Ligand_Rearrangement_Leads_to_Tetrahydrothiophene-Functionalized_N_S-Heterocyclic_Carbene_Palladium_II_Complexes/13633301

Since our lab’s first paper establishing a transient directing group strategy for asymmetric Heck-type hydroarylation went online in 2019, we’ve been hard at work trying to extend this approach to three-component 1,2-difunctionalization. At long last we’ve succeeded, and we are thrilled to report the fruits of our labor: a remarkably versatile 1,2-arylfluorination reaction that can form fully substituted C(sp³)–Ar and C(sp³)–F stereo centers in up to >99% ee. Pivotal to the success of the project was use of design of experiments (DoE) to facilitate rapid optimization of reaction conditions and reaction progress kinetic analysis (RPKA) to elucidate the reaction mechanism. Hats off to Zhonglin, Luke, Mingyu, Zi-Qi, Van, and Yang on the landmark achievement!

For a link, click here: https://chemrxiv.org/articles/preprint/A_Transient_Directing_Group_Strategy_Enables_Enantioselective_Multicomponent_Organofluorine_Synthesis/13537283

The holiday paper flurry continues! ❄️⛄️🥶 This time it’s Team Nickel, who together with collaborators at Bristol Myers Squibb describe the use of Ni(COD)(DMFU) as a well-defined, all-in-one precatalyst for alkene diarylation. This lovely red free-flowing solid can be conveniently prepared in high yield from Ni(COD)₂ and is indefinitely thermally stable as long as handled in an inert-atmosphere glovebox. Congrats to the Scripps team, Nana, Van, and Omar, as well as BMS team, Steve and Martin. Here’s to another great year to come in the Scripps–BMS collaboration!

For a link to the paper, click here: https://www.thieme-connect.com/products/ejournals/abstract/10.1055/a-1344-6040