L-selectride

L-selectride is a organoboron compound with the chemical formula Li[(CH3CH2CH(CH3))3BH].

[1] Like other borohydrides, reductions are effected in two steps: delivery of the hydride equivalent to give the lithium alkoxide followed by hydrolytic workup: The selectivity of this reagent is illustrated by its reduction of all three methylcyclohexanones to the less stable methylcyclohexanols in >98% yield.

Under certain conditions, L-selectride can selectively reduce enones by conjugate addition of hydride, owing to the greater steric hindrance the bulky hydride reagent experiences at the carbonyl carbon relative to the (also-electrophilic) β-position.

[2] L-Selectride can also stereoselectively reduce carbonyl groups in a 1,2-fashion, again due to the steric nature of the hydride reagent.

These reagents can sometimes be used as alternatives to, for instance, sodium amalgam reductions in inorganic chemistry.