Borane 1,1,2-trimethylpropyll-

Alternatively, a-chiral ketones can be prepared from dialkyl-(l,l,2-trimethylpropyl)boranes by cyanidation (method ), carbonylation (method ( )) or the haloalkyne route (method )9. 

The trialkylborane is derived from monoalkyl-(l,l,2-trimethylpropyl)borane by hydroboration. Care must be taken in the oxidation step leading to the a-chiral ketones and buffering is necessary to avoid racemization. However, even with these precautions, 2-6% racemization is observed in some cases9,20. The intermediate alkenyl-(l,l,2-trimethylpropyl)borinates are relatively resistant to oxidation thus prolonged reaction times or higher temperatures are sometimes required to complete the reaction via the haloalkyne route. 

The reduction of several hydroxyketones to cisjtrans mixtures of the corresponding diols by diborane, (l,l,2-trimethylpropyl)borane, and monochloro-borane has been studied as has the 9-BBN reduction of phenalanone to phenalene. ... 

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