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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 ...
Some amides can be reduced to aldehydes in the Sonn-Müller method, but most routes to aldehydes involve a well-chosen organometallic reductant. Lithium aluminum hydride reduces an excess of N,N-disubstituted amides to an aldehyde: [citation needed] R(CO)NRR' + LiAlH 4 → RCHO + HNRR' With further reduction the alcohol is obtained.
Since, aldehydes reduce more easily than ketones, they require milder reagents and milder conditions. At the other extreme, carboxylic acids, amides, and esters are poorly electrophilic and require strong reducing agents. [17] The idealized equation for the reduction of a ketone by sodium borohydride is: 4 RCOR' + NaBH 4 → NaB(OCHRR') 4
The intermediate imine can be isolated or reacted in-situ with a suitable reducing agent (e.g., sodium borohydride) to produce the amine product. [2] Intramolecular reductive amination can also occur to afford a cyclic amine product if the amine and carbonyl are on the same molecule of starting material. [4]
Tosyl group (blue) with a generic "R" group attached Tosylate group with a generic "R" group attached. Note the extra oxygen, compared to plain tosyl. In organic chemistry, a toluenesulfonyl group (tosyl group, abbreviated Ts or Tos [nb 1]) is a univalent functional group with the chemical formula −SO 2 −C 6 H 4 −CH 3.
Lithium borohydride (LiBH 4) is a borohydride and known in organic synthesis as a reducing agent for esters.Although less common than the related sodium borohydride, the lithium salt offers some advantages, being a stronger reducing agent and highly soluble in ethers, whilst remaining safer to handle than lithium aluminium hydride.
These conversions are metathesis reactions, and the hydricity of the product is generally less than of the hydride donor. Classical (and relatively cheap) hydride donor reagents include sodium borohydride and lithium aluminium hydride. In the laboratory, more control is often offered by "mixed hydrides" such as lithium triethylborohydride and ...
The table below summarizes the reductions that may be carried out with a variety of metal aluminium hydrides and borohydrides. The symbol "+" indicates that reduction does occur, "-" indicates that reduction does not occur, "±" indicates that reduction depends on the structure of the substrate, and "0" indicates a lack of literature information.