Nopol synthesis

The synthesis of (S)-enantiomer of propargyl alcohol is achieved by Alpine-Bo-rane obtained from (-)-a-pinene. However, (-)-a-pinene is an expensive reagent. Consequently, structurally related nopol, 6,6-dimethylbicyclo[3.1.1]hept-2-en-2-ethanol, which is a low-cost and commercial alternative to (-)-a-pinene is used. Nopol, after conversion to benzyl ether is hydroborated [1,2] with 9-BBN on reflux in THF overnight to give the borane NB-Enantrane [2] (Scheme 26.3). 

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