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Luche reduction is the selective organic reduction of α,β-unsaturated ketones to allylic alcohols. [ 1 ] [ 2 ] [ 3 ] The active reductant is described as "cerium borohydride", which is generated in situ from NaBH 4 and CeCl 3 (H 2 O) 7 .
Carbonyl reduction, the net addition of H 2 across a carbon-oxygen double bond, is an important way to prepare alcohols. Stoichiometric reducing agents to accomplish this task include lithium aluminium hydride , sodium borohydride , alkoxy borohydrides, alkoxy aluminium hydrides, and boranes.
Sodium borohydride, also known as sodium tetrahydridoborate and sodium tetrahydroborate, [5] is an inorganic compound with the formula Na B H 4 (sometimes written as Na[BH 4]). It is a white crystalline solid, usually encountered as an aqueous basic solution. Sodium borohydride is a reducing agent that finds application in papermaking and dye ...
In organic chemistry, carbonyl reduction is the conversion of any carbonyl group, usually to an alcohol. It is a common transformation that is practiced in many ways. [ 1 ] Ketones , aldehydes , carboxylic acids , esters , amides , and acid halides - some of the most pervasive functional groups , -comprise carbonyl compounds.
The carbonyl is first treated with ammonia to promote imine formation by nucleophilic attack. The imine is then reduced to an amine by sodium cyanoborohydride. This reaction works on both aldehydes and ketones. The carbonyl can be treated with ammonia, a primary amine, or a secondary amine to produce, respectively, 1°, 2°, and 3° amines. [5]
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 ...
Starting with the aluminium alkoxide 1, a carbonyl oxygen is coordinated to achieve the tetra coordinated aluminium intermediate 2. Between intermediates 2 and 3 the hydride is transferred to the carbonyl from the alkoxy ligand via a pericyclic mechanism. At this point the new carbonyl dissociates and gives the tricoordinated aluminium species 4.
In the generally accepted mechanism proposed by Rudolf Criegee in 1953, [11] [12] [13] the alkene and ozone form an intermediate molozonide in a 1,3-dipolar cycloaddition. Next, the molozonide reverts to its corresponding carbonyl oxide (also called the Criegee intermediate or Criegee zwitterion ) and aldehyde or ketone ( 3 ) in a retro-1,3 ...