ChemInform Abstract: A Catalytic Borylation/Dehalogenation Route to o‐Fluoro Arylboronates.

Abstract

A Catalytic Borylation/Dehalogenation Route to o-Fluoro Arylboronates. -If ammonium formate is used as the hydrogen source instead of PMHS, the dehalogenation is often accompanied by deborylation. An intramolecular competition experiment reveals the debromination being faster than the dechlorination, thus allowing selective removal of bromine in the presence of chlorine. Some products are contaminated with small amounts of regioisomerically borylated compounds. -(JAYASUNDARA, C. R. K.; UNOLD, J. M.; OPPENHEIMER, J.; SMITH, M. R.; MALECZKA*, R. E. J.; Org. Lett. 16 (2014) 23, 6072-6075, http://dx.

Merging Iridium-Catalyzed C–H Borylations with Palladium-Catalyzed Cross-Couplings Using Triorganoindium Reagents

“…Despite the potential for competing self-polymerization, 2 halogen bearing arylboronates have been made to undergo chemoselective bond forming reactions with a C−X group where the boronic ester remains intact for subsequent chemistry. 3,4 Reactions of haloarenes bearing N-methyliminodiacetic acid 5−10 and 1,8-diaminonaphthalene 11,12 boronic esters (BMIDA and BDAN, respectively) avoid unwanted polyphenylene formation, as they are unreactive under certain Suzuki conditions (Scheme 1a). Such borylated biaryls have been employed in iterative Pd-catalyzed Suzuki−Miyaura cross-couplings popularized by Burke and others.…”

“…We have observed the same phenomena in past efforts to telescope CHB and subsequent Pd-catalyzed transformations. 4 We attribute this trend to residuals from the CHB step causing a loss of catalytic activity.…”