19 votes
Accepted

Why does LiAlH4 reduce an amide to an amine, but only reduce a ketone/aldehyde to an alcohol?

You've got it correct in your comment with the $\ce{N}$ lone pair assisting. The reason why the $\ce{N}$ lone pair kicks oxygen out, and not the other way round, is because oxygen-based groups are ...
orthocresol's user avatar
  • 70.9k
16 votes
Accepted

Why does LiAlH4 reduce the double bond of cinnamaldehyde, whereas NaBH4 does not?

Cinnamaldehyde (1) does not undergo 1,4-reduction but rather 1,2-reduction with LiAlH4. The product of the reduction is 3-phenylpropan-1-ol (2). If conjugate addition were to occur, enolate 3 would be ...
user55119's user avatar
  • 16.5k
15 votes
Accepted

Regioselectivity of epoxide hydrogenation using Pt versus Ni catalyst

First of all, I should clarify that hydrogenolysis of epoxides does not always proceed with such predictable regioselectivity simply based on a switch in catalyst. Often it depends on the substituents ...
orthocresol's user avatar
  • 70.9k
13 votes

Are groups other than carbonyl reduced by Clemmensen reduction?

I would look at it in the following way: The oxidation state of the carbonyl carbon is +II, while the oxidation state of the nitrogen in the nitro group is +III. So nitrogen is in a higher oxidation ...
logical x 2's user avatar
  • 2,794
12 votes
Accepted

Can Mg/ether reduce carbonyl groups?

It is known that $\ce{Mg}$ will reduce ketones. The articles (Ref.1 and 2) in the References section confirm this fact. If you want to form the Grignard reagent of a molecule that also happens to ...
Waylander's user avatar
  • 21.9k
11 votes
Accepted

Reaction of phenol and zinc dust

Ludwig Gattermann's The Practical Methods of Organic Chemistry (translated into English, 1896) has two references to reduction of aromatics with zinc dust: The first one refers to Liebigs Annalen, ...
Karsten's user avatar
  • 39.8k
10 votes

Can protection group be used in a Wolff–Kishner reaction?

@Halake: The protection of adipaldehyde as the monoacetal was solved by Schreiber and Claus some years ago [Also see, Schreiber, S.L.; Claus, R.E.; Reagan, J. Tetrahedron Letters, 1982, 23, 3867.] ...
user55119's user avatar
  • 16.5k
10 votes
Accepted

Why can't terminal alkynes take part in Birch reduction?

The alkyne proton is acidic enough to react with the dissolving metal to give the anion, giving the metal alkynide as it shown by these procedures sodium acetylide prep, sodium phenylacetylide prep; ...
Waylander's user avatar
  • 21.9k
10 votes
Accepted

Reduction of carbamate with LAH

Carbamates are usually reduced to N-methyl groups. There are numerous examples: J. Am. Chem. Soc. 2012, 134 (16), 6936–6939 Org. Lett. 2012, 14 (18), 4834–4837 But it is not always a given. In this ...
orthocresol's user avatar
  • 70.9k
10 votes
Accepted

Why does Birch reduction of naphthalene with isoamyl alcohol form tetralin instead of 1,4-dihydrodialin (as formed with C2H5OH)?

As I noted in a Comment that there should be no significant difference between the use of ethanol or isoamyl alcohol in the reduction of naphthalene with sodium in that both alcohols are primary. The ...
user55119's user avatar
  • 16.5k
10 votes
Accepted

On the use of hexane in the organic reduction by DIBAL-H

Unlike other reducing metal hydrides (e.g., $\ce{NaBH4}$ and $\ce{LiAlH4}$), diisobutylaluminum hydride (DIBAL-H) is a liquid at room temperature and dissolve in many hydrocarbons such as toluene and ...
Mathew Mahindaratne's user avatar
10 votes

What is the major product in the reaction between 4-chloropentanal and lithium aluminium hydride?

It will depend on strict control of the equivalents of reductant, your work-up conditions and your control of temperature during the workup. The intial product of the reduction is the aluminium ...
Waylander's user avatar
  • 21.9k
9 votes
Accepted

What are the different types of catalysts used in catalytic hydrogenation of alkynes?

The "Lindlar catalyst" (Pd/CaCO3) is probably the most common way of effecting stereoselective reduction of alkynes to (Z)-alkenes. It is fairly accessible and the reaction is easy to run. ...
orthocresol's user avatar
  • 70.9k
9 votes

What is the major product in the reaction between 4-chloropentanal and lithium aluminium hydride?

The reduction of alkyl halides to the corresponding alkane by $\ce{LiAlH4}$ is well known reaction (For example, see Ref.1): $$\ce{R-X + LiAlH4 -> R-H + AlH3 + LiX}$$ The mechanism of this reaction ...
Mathew Mahindaratne's user avatar
8 votes

Does RedP+HI reduce all carbon functional groups to alkane?

Nope, in general it doesn't. You are correct. See also for example: A. Aramini, M. R. Sablone, G. Bianchini, A. Amore, M. Fanì, P. Perrone, A. Dolce, M. Allegretti, Tetrahedron 2009, 65 2015–2021. ...
Outlander's user avatar
  • 1,603
8 votes
Accepted

Hydroboration oxidation reaction on trans,trans,trans-1,5,9-cyclododecatriene with carbon monoxide

You guessed it right: a ketone will be formed. This reaction involves migration of alkyl groups from boron to the carbon atom of CO. There will be three migrations after which you will get your ...
amish dua's user avatar
  • 628
8 votes

Why does the Rosenmund reduction stop at the aldehyde stage?

In general, the Rosenmund reduction isn't actually used very often, mainly since the catalyst is also very good at reducing other functional groups which may be present in the molecule (the catalyst ...
NotEvans.'s user avatar
  • 17.1k
8 votes
Accepted

Dehydration of carboxylic acids with phosphoric acid

The $\ce{-OH}$ part will not get protonated, since its lone pair is in resonance with the carbonyl part of the $\ce{-COOH}$ group. Instead, the lone pair of the carbonyl part will give its lone pair ...
Ronak Singha's user avatar
8 votes
Accepted

Could sodium in ethanol reduce amides to amines?

Yes, that is used as a pathway for synthesis of amines from amides, albeit rarely. I quote from the abstract of a communication that reports the same: (emphasis mine) The reduction of amides to ...
William R. Ebenezer's user avatar
8 votes

Selective reduction of nitro group to amine, in benzene ring containing nitrile?

My answer is intended to support Waylander's suggestion elsewhere. I thought it'd be better to give OP some insight of this reduction mentioned (Ref.1). To my knowledge, after doing thorough ...
Mathew Mahindaratne's user avatar
8 votes
Accepted

Photochemical reduction of benzophenone: why inverted flask?

I think the reason for inverting the the round flask is to capture sunlight very efficiently. A round bottomed flask filled with a fluid is like a ball lens. Sun rays can be considered parallel and ...
AChem's user avatar
  • 39.8k
7 votes
Accepted

Does DIBAL-H reduce carboxylic acids?

Does diisobutylaluminium hydride (DIBAL-H) reduce only carboxylic acids? or only carboxylic acid esters? or reduce both both types of compounds? The answer is yes, it does reduce both. Not only them,...
Mathew Mahindaratne's user avatar
7 votes

Kinetic isotope effect in nitration of benzene

Page 513 of Organic Reaction Mechanisms by Bansal references the work of Melander in Arkiv för Kemi, 2, 211 (1950). This states that the rates of nitration for benzene vs benzene-d6 are about the same,...
Beerhunter's user avatar
  • 2,201
7 votes

Out of the given reagents, find the ones to be used to convert benzene to p-aminophenol

Steps: Use $\ce{Br2/FeBr3}$ to make bromobenzene. Nitrate with $\ce{HNO3/H2SO4}$ to make 4-bromo-nitrobenzene. Treat with $\ce{NaOH}$ to displace the $\ce{Br}$ making 4-nitrophenol. Reduce with $\ce{...
Waylander's user avatar
  • 21.9k
7 votes
Accepted

Are there any reducing agents for reduction of nitrobenzene to aniline other than Sn/HCl?

Hydrogenation of aromatic nitro groups (over, for example, $\ce{Pd/C}$) usually results in reduction to the corresponding aniline and is probably easier to carry out and work up as compared to $\ce{Sn/...
orthocresol's user avatar
  • 70.9k
6 votes
Accepted

Does a non-terminal alkyne react with sodamide?

By the given question conditions you should easily guess that $(A)$ is $\ce {Hex-2-yne}$. When it is reacted with $\ce{NaNH_2}$ in presence of heat it can isomerise to terminal alkyne by following ...
Soumik Das's user avatar
  • 5,643
6 votes
Accepted

Birch reduction of anisole

Chemistry is an experimental science supported by computational methods. Qualitative explanations for reaction mechanisms follow as a result. More on that issue later.The mechanism of the Birch ...
user55119's user avatar
  • 16.5k
6 votes

Why does reduction using sodium borohydride require a protic solvent?

The roles of a protic solvent and lithium and magnesium salts can be tied together in their role as electrophiles—and they impact both solubility and reactivity. Protic Hydrogen's evil twin Sodium ...
Oscar Lanzi's user avatar
  • 55.7k
6 votes
Accepted

What side reactions are suppressed by the use of TMSCl in the acyloin condensation?

The acyloin condensation of diethyl adipate (1) on your Wikipedia citation generates ethoxide that can cause a Dieckmann condensation (intramolecular Claisen condensation, structure 6). TMSCl ...
user55119's user avatar
  • 16.5k
6 votes

Selective reduction of nitro group to amine, in benzene ring containing nitrile?

$\ce{SnCl2.2H2O}$ in refluxing $\ce{EtOAc}$ as reported by Bellamy & Ou here will do this very cleanly. Work up into ice then add concentrated $\ce{NaOH}$ until you get phase separation. I have ...
Waylander's user avatar
  • 21.9k

Only top scored, non community-wiki answers of a minimum length are eligible