Dehydrogenation of amine-boranes

[1] The dehydrogenation of AB would in principle afford (H2BNH2)n and (HBNH)n. The monomers (n = 1) are highly unstable with respect to oligomerization.

[2] Secondary amine-boranes dehydrogenate to form cyclic dimers, or monomeric aminoboranes in the case of more bulky groups on the amine.

[1] As in the case with the metal carbonyl catalysts, bulky secondary amine-boranes form monomeric aminoboranes.

[5] In contrast to these systems, the cationic zirconocene complex [Cp2ZrOC6H4P(tBu)2]+ effectively catalyzes the reaction, with the most notable example being the dehydrogenation of dimethylamineborane in 10min at room temperature.

[5] Dehydrogenation of amine-boranes is thermodynamically favourable, making the process attractive for hydrogen storage systems.

Amine-borane dehydrogenation can be coupled with hydride transfer to unsaturated functional groups, usually olefins in an anti-Markovnikov fashion.