Alkaline‐Earth‐Catalyzed Dehydrocoupling of Amines and Boranes

Abstract

Dehydrocoupling reactions between the boranes HBpin and 9-borabicyclo[3.3.1]nonane and a range of amines and anilines ensue under very mild reaction conditions in the presence of a simple β-diketiminato magnesium n-butyl precatalyst. The facility of the reactions is suggested to be a function of the Lewis acidity of the borane substrate, and is dictated by resultant pre-equilibria between, and the relative stability of, magnesium hydride and borohydride intermediates during the course of the catalysis.

Magnesium‐Catalyzed Tandem Dehydrogenation‐Dehydrocoupling: An Atom Economical Access to Alkynylboranes

“…We envisioned this property could be used to regenerate the alkynide instead of leading to hydromagnesiation like in Ma and Rueping's examples . This would provide the first magnesium catalyzed C−H/B−H dehydrocoupling as, to our knowledge, only heteroatom–boron bonds have been formed through dehydrocoupling using Group 2 metal catalysis (Scheme ) …”

Molecular Magnesium Hydrides

“…[9,10] Conscious efforts have been made to obtain aw ide variety of composition and nuclearity ranging from mononuclear terminal hydrides [10e,g,-j,u,w] to clusters. [10t] Apart from being models for hydrogen-storage materials,s ome of the hydrides have been identified as key intermediates in catalytic reactions,s uch as hydroboration, [10m, 11] hydrosilylation, [12] CO homologation, [12c,d] and dehydrogenative coupling between amine and hydroborane, [13] amine and hydrosilane, [14] and TEMPO and hydrosilane. [10t] Apart from being models for hydrogen-storage materials,s ome of the hydrides have been identified as key intermediates in catalytic reactions,s uch as hydroboration, [10m, 11] hydrosilylation, [12] CO homologation, [12c,d] and dehydrogenative coupling between amine and hydroborane, [13] amine and hydrosilane, [14] and TEMPO and hydrosilane.…”

“…[9, 10i,k,n,o,q,r,t] Af ew cationic hydride clusters have been isolated as well. [10t] Apart from being models for hydrogen-storage materials,s ome of the hydrides have been identified as key intermediates in catalytic reactions,s uch as hydroboration, [10m, 11] hydrosilylation, [12] CO homologation, [12c,d] and dehydrogenative coupling between amine and hydroborane, [13] amine and hydrosilane, [14] and TEMPO and hydrosilane. [15] Therapidly growing interest prompted us to highlight the features of the molecular magnesium hydrides reported till date.M olecular s-block metal hydrides including those of Group 2h ave been reviewed in the past.…”

O2‐Mediated Oxidation of Aminoboranes through 1,2‐N Migration

“…[11] Functionalization methods for C À Bb onds are well established. [13] Conversely,a lthough methods for the synthesis of aminoboranes have significantly advanced, [14] their application lags disturbingly behind. [13] Conversely,a lthough methods for the synthesis of aminoboranes have significantly advanced, [14] their application lags disturbingly behind.…”