Selective Formation of a 1,2‐Diborane(4) and Alcohol‐Driven B─B Bond Cleavage to Generate H 2
Rayni P. Noriega, David J. Nelson, Marcus W. DroverABSTRACT
Diborane(4) chemistry continues to reveal new aspects of the reactivity of electron‐deficient p ‐block elements. These systems are capable of bond activation and ligand rearrangement—processes once thought to be exclusive to transition metals. Here, we show that reaction of B 2 Cat 2 (Cat = benzene‐1,2‐diolate) with mesityllithium (MesLi; Mes = 2,4,6‐trimethylphenyl) affords an unusual 1,2‐disubstituted diborane(4), Mes–B(μ‐Cat)–B–Mes. Structural, spectroscopic, and computational data indicate that the catecholate co‐ligand favors formation of the 1,2‐isomer. Subsequent reaction with alcohols (ROH) cleaves the B─B bond in this compound to form CatBMes and MesB(OR) 2 via B(II) → B(III) oxidation, releasing H 2 . These results expand the reactive landscape of O,O ‐chelating diborane(4) systems, establish an entry into 1,2‐diborane(4) frameworks, and demonstrate that their distinct reactivity toward alcohols can be exploited to differentiate the chemistry of 1,1‐ and 1,2‐diborane(4) isomers.