Questions tagged [pericyclic]
For questions concerning all aspects of pericyclic reactions, their use in synthesis, and the orbital analyses used to describe them.
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What do the pi antibonding orbitals of 1,5-hexadiene look like?
Hi so right now I'm learning about the Cope and Claisen rearrangements, and often something is shown where the antibonding pi orbitals of the two alkenes have to overlap in a certain way, like in the ...
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How do I decide on supra-supra/supra-antara and thermally/photochemically when the educt and product of the sigmatropic rearrangment is given?
Was the given product of this [1,5]-sigmatropic rearrangement reached thermally with orbitals suprafacial-suprafacial or photochemically with orbitals suprafacial-antarafacial?
The same question goes ...
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Identification of endo and exo products in this Diels-Alder reaction
This synthesis example is shown in the book Cycloaddition Reactions in Organic Synthesis by S. Kobayashi and K. A. Jorgensen (link), on p. 15:
8 is a chiral catalyst, which can be ignored, in the ...
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Can endo and exo products occur when the diene is not cyclic?
I have always thought that the diene needs to be cyclic for there to be endo and exo products. Perhaps, I formed this impression because most textbook examples that are used to illustrate the concept ...
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Website or Software for Molecular Orbital Rotations
Does anyone know what software or website allows viewers to see rotation of orbitals in a molecule such as conrotatory and disrotatory directions? I'm not an expert in this field sorry. I tried VR ...
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Frontier orbital analysis of zinc-catalysed carbonyl-ene reaction
Q1. Is the $\sigma_\ce{C-H}$ bond a donor in this reaction? If not, then can we take the alternate combination (HOMO of alkene, LUMO of the $\ce{C-H}$ bond and, HOMO of the carbonyl)?
Q2. We can also ...
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Can cycloaddition reactions be antarafacial?
Cycloaddition reactions of the form [4+2] and [2+2] are always suprafacial, as the geometry is too constrained to allow for antarafacial interaction between the FMO's. However, for cycloaddition of ...
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How do bonds rotate in pericyclic reactions?
In Pericyclic reactions, it is shown that the terminal bonds rotate (conrotation or disrotation) to allow for allignment of the FMO's, thereby forming the sigma bond
However, a detail that most of my ...
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Retro Diels–Alder reaction in synthesis of corallopyronin A
I was looking at the synthesis of corallopyronin A in the following paper by Rentsch and Kalesse: Angew. Chem. Int. Ed. 2012, 51 (45), 11381–11384.
There is one reaction which is described as
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Use of TsN3, toluene at high temperature
My reasoning:
My understanding is in first step the alcohol’s O- does an Sn2 attack on the OTs containing carbon. In the second step I am confused where does the reaction happen in the triple bond or ...
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Can Diels-Alder reaction occur using reagents of Robinson annulation?
Robinson annulation seemed somewhat like the Diels-Alder reaction to me, if all ketonic groups were to be represented as enol then cyclohexanone would be like diene and the Michael acceptor as a ...
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Focusing on HOMO when discussing thermal electrocyclic reactions
When taking into consideration the outcome of a thermal electrocyclic reaction, why do we focus specifically on the HOMO of the conjugated polyene? Why does it seemingly have the highest contribution ...
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Cis, trans diene reacting with trans dienophile in D-A reaction
I wonder if I predicted the products correctly, because it seems to be messier than I thought - there's a pair of diastereomers... Also, I feel that the endo/exo rule does not apply here. Am I correct ...
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Are alkenes or alkynes reduced first with diimide?
I know that $\ce{NH2NH2}/\ce{H2O2}$ is used as an reducing agent for selective reduction of alkenes and alkynes. $\ce{NH2NH2}$ reacts with $\ce{H2O2}$ to form diimide ($\ce{N2H2}$), which then ...
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Does the reaction of 2‐hydroxy‐6‐methyl‐5‐nitrocyclohepta‐2,4,6‐trien‐1‐one with NaOH involve ring contraction?
What is the product and mechanism when 2‐hydroxy‐6‐methyl‐5‐nitrocyclohepta‐2,4,6‐trien‐1‐one is reacted with
$\ce{NaOH}$?
The only reagent used is $\ce{NaOH}$ so I suppose it abstracts the ...
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