Optimization. In efforts to find a ligand for chelation to Pd that leads to an effective catalyst under aqueous micellar coinditions, naphthalen-1-yl sulfurofluoridate (1a) and 4-aminoacetophenone (1b), as model substrates, were selected for initial amination studies (Table ). Based on our prior aminations of aryl halides, 50a, b reactions were run starting with catalytic amounts of Colacot's readily available and bench stable dimeric species [Pd(crotyl)Cl]2 as the source of Pd(II) in 2 wt % Savie as the aqueous reaction medium. Potassium t-butoxide (KOtBu) was selected since aryl amination protocols tend to utilize alkoxide bases. An initial investment of 0.25 mol % of Pd dimer (hence, 0.5 mol % [Pd]; administered as a stock solution in THF; see SI, section 3) was made. The key to success, and to eventually focus on OAC-1, was the eventual finding that the ligand BippyPhos complexed with Pd efficiently mediated C-N bond construction (entry 3; see SI, section 3.1 for the complete list of ligands screened). Among other ligands evaluated, none led to productive C-N couplings (entries 1-2 and 5-7). Screening bases (see SI, section 3.2) indicated that milder conditions would be necessary, as aryl fluorosulfates are known to undergo sulfamation in the presence of amines under strongly basic conditions. Ultimately, Et3N (entry 11) proved to be the most effective base, affording biarylamine 1 in 98% yield (as determined by H NMR; 92% isolated). Other weak bases such as Cs2CO3 and Proton Sponge proved equally effective; however, considering cost, Et3N turned out to be the base of choice. Screening co-solvents led to use of 10 v/v % cyclopentyl methyl ether (CPME), a greener alternative to THF and 2-MeTHF (entry 15). Of note is that these aminations also work efficiently using no co-solvent (entry 16), which may be of considerable value if used at industrial scales. Also worth pointing out as foreshadowing, full conversion was observed within a 2 h period under these reaction conditions (i.e., a global concentration of 0.5 M).