15 votes
Accepted

Why does NOCl dissociate as +NO and Cl-?

Firstly, the correct comparison to make to determine which is more likely of $\ce{NO+}+\ce{Cl-}$ and $\ce{NO-}+\ce{Cl+}$ is the ionization potential vs. the electron affinity of the the two species. ...
levineds's user avatar
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7 votes
Accepted

Stereochemistry of nitrosyl chloride addition to an alkene

Syn or anti addition is difficult to resolve with propene because the final product admits rotation about the single bond. However, if the rotation is constrained or the relative positions of the ...
Oscar Lanzi's user avatar
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6 votes

Can enamines be formed from α,β-unsaturated ketones?

Stork and Birnbaum have reported (Tetrahedron Lett. 1961, 10, 313) the formation of dienamine 2 from octalone 1. Alkylation with methyl iodide leads to α-alkylation of the dienamine. Buffer conditions ...
user55119's user avatar
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5 votes

Stereochemistry of nitrosyl chloride addition to an alkene

The most important fact about this question is the stereochemistry of nitrosyl chloride $(\ce{NOCl})$ addition to an alkene. The OP has wondered whether it follows syn- or anti-addition. The answer is ...
Mathew Mahindaratne's user avatar
5 votes

Cram's rule for nucleophilic addition to carbonyl groups

Cram's rule, proposed by Donald Cram in 1952,[1] was the earliest model proposed for rationalising the stereoselectivity of nucleophilic additions to carbonyl groups with α-stereocentres. The model ...
orthocresol's user avatar
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5 votes

Effect of protecting group on diastereoselectivity of LiAlH4 reduction of α-hydroxyketones

I think Jan did an excellent job of answering your question, however I am writing a slightly longer answer largely with more details concerning the Felkin–Anh rule, just so that someone who is not ...
getafix's user avatar
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4 votes

Effect of protecting group on diastereoselectivity of LiAlH4 reduction of α-hydroxyketones

The $\ce{TBDPS}$ group (tert-butyldiphenylsilyl) is a very bulky protecting group. A silicon atom is bonded to the oxygen, which already acts as a larger carbon atom. That is then substituted by three ...
Jan's user avatar
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4 votes

Isocyanides undergo addition reactions, but cyanides do not. Why?

Isocyanide can undergo addition reaction due to the fact that it is capable to attach both the electrophile and nucleophile in the same carbon atom while it is not achieved by cyanide. The negative ...
Nilay Ghosh's user avatar
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3 votes
Accepted

What is the driving force for imine formation?

In practice, a drying agent is sometimes added to the reaction: I've used molecular sieves before, but a cursory database search brings up a few other options, e.g. magnesium sulfate, silica gel, or ...
orthocresol's user avatar
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2 votes

Mechanism for cyclic enamine formation after N-Boc deprotection

Those conditions just give the amine. One you have an amine and an aldehyde or ketone, you should form an imine or iminium ion. Imines are relatively stable, but secondary amines, such as the one in ...
Zhe's user avatar
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2 votes

difference between elimination reactions and oxidation reactions

Whether the oxidation of an alochol or the reduction of a carbonyl group follows a certain mechanism depends on the reagents/conditions. For example: The sodium borohydride reduction of a ketone ...
Ben Norris's user avatar
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1 vote

Electrophilic addition to benzene

This is an electrophillic reaction. These reactions make cationic intermediates. There's never been a question about stabilizing intermediate carbanions in electrophillic reactions. Thus, you are ...
Mathew Mahindaratne's user avatar
1 vote

Carbocation Stability: Tertiary versus Secondary Benzyl for Hydrobromic Acid Addition

In the first instance, bromine will attach itself on the benzylic carbon as the benzylic carbocation formed in this case would be more stable than than the tertiary carbocation due to the mesomeric ...
Siddharth Porwal's user avatar

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