21 votes
Accepted

Why is 1H-borepine aromatic?

1H-borepine is isoelectronic to the cycloheptatrienyl cation. In both cases, you have a planar ring of seven atoms, whose hybridisation is close enough to $\mathrm{sp^2}$ to allow for a third p-...
Jan's user avatar
  • 67.8k
17 votes
Accepted

What happens when an alkylborane is treated with acetic acid?

Acetic acid effects protonolysis of the borane: If AcOD is used then RD (instead of RH) is formed.
orthocresol's user avatar
  • 70.9k
14 votes
Accepted

Why does boron add to the less substituted carbon in the hydroboration of an alkene?

For the hydroboration of isobutene there is a steric aspect: And though sterics may play some part, it doesn't explain near 100% regioselectivity. More important in determining regiochemistry, I ...
ringo's user avatar
  • 24k
11 votes
Accepted

What is the mechanism for the reaction of alkenes with diborane and chloramine?

Organoboranes react with chloramine to give the corresponding amine as reported by Brown et al. [1], so P is n-propylamine (propan‐1‐amine). The mechanism is similar to the oxidation of boranes using ...
Waylander's user avatar
  • 22k
9 votes

What is the mechanism for the reaction of alkenes with diborane and chloramine?

I like Waylander's answer, which is 100% correct. However, I have a little concern about the question itself. The conditions given in OP's question are not exactly correct. It may mislead the viewers ...
Mathew Mahindaratne's user avatar
7 votes

Is it possible to make a carbon icosahedron?

Probably not an icosahedron. We might have better results with a smaller cluster, such as four atoms. One major difficulty is the fact that isoelectronic replacement of boron with carbon introduces a ...
Oscar Lanzi's user avatar
  • 55.9k
6 votes

Does boric acid really rearrange phenols?

Prepchem.com apparently misinterpreted what was in the patent. The abstract of the patent reads: A process for preparing hydroxyphenyl ethers by oxidizing phenyl ethers with hydrogen peroxide in the ...
Oscar Lanzi's user avatar
  • 55.9k
5 votes
Accepted

Is 1,2-dihydro-1,2-diborete aromatic?

That molecule is indeed aromatic. It satisfies Hückel's rule $(4n+2)$ with $n=0$. It's also planar. Lastly, the boron atom is bonded to three other atoms, meaning it can exist with $\mathrm{sp^2}$ ...
turnt's user avatar
  • 517
4 votes

In hydroboration oxidation reaction .. why do not we use sodium hydroxide alone as a nuclophile?

The combination of hydroxide and peroxide is essential for the oxidation of boranes to alcohol, both components are needed. Firstly the hydroxide deprotonates peroxide to give peroxide anion - a good ...
Waylander's user avatar
  • 22k
3 votes
Accepted

Stereoselectivity of Roush crotylboration

This figure from this reference (p. 170). might help you visualize things. As you can see, the stereochemistry is given by electronic repulsion between the carbonyl group and the incoming aldehyde.
ralk912's user avatar
  • 1,539
2 votes

Hydroboration–oxidation reaction without THF

Borane dimerises to diborane which does all the reactions of borane, including hydroborating alkenes. Diborane gas is commercially available if you wish to use it rather than stabilised borane, and ...
Waylander's user avatar
  • 22k
2 votes
Accepted

Why is an alkoxide released instead of hydroxide in the attack of trialkyloxyborane by hydroxide?

Both hydroxide and alcoholate can be displaced from the tetracoordinated intermediate. The difference is that displacing the hydroxide is just the back reaction of the inital attack while displacing ...
Jan's user avatar
  • 67.8k
1 vote

Hydroboration/oxidation vs acid-catalyzed hydration of 1-phenylpropene

Hydroboration With the simplest hydroborating agent $\ce{BH3.THF}$, the hydroboration/oxidation of 1-phenylpropene proceeds to give 1-phenylpropan-1-ol as the major product.[1] The isomer of the ...
orthocresol's user avatar
  • 70.9k

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