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