Experiment 5- Diels Alder Reaction Flashcards
What is characteristic of a stepwise mechanism?
The formation of some sort of intermediate, like the carbocation in SN1 reactions.
What are the 2 main differences between concerted and stepwise mechanisms?
In concerted mechanisms, bond breaking and forming happens simultaneously with the potential of FORMING MULTIPLE bonds at the same time.
Which of the following is NOT a concerted reaction?
SN1.
Define Pericyclic Reactions
Concerted reactions that occur through cyclic transition states.
Define Cycloadditions
Pericyclic reactions that involve the formation of 2 sigma bonds.
What are the 2 main involved species in the Diels-Alder reaction?
The diene and the conjugated diene.
What are the 2 configurations that can be adopted in the Diels-Alder reaction product? Differentiate between the two.
The exo and the ends product. Exo is a more stable product compared to endo due to minimized steric clash. Endo T.S is lower in energy compared to exo due to secondary orbital overlap between the diene and dienophile, making it the kinetic product. Exo is the thermodynamic product.
What is the relationship between the exo and endo product?
Diastereomers.
What is the endo-rule?
Under normal circumstances, in the absence of high temperature and time, the endo product is favored.
Why does the Exo product form more when furan is the diene?
Since furan is a highly stable compound due to aromaticity, the hypothesis was the formation of more exo product. As time passes, equilibrium is reached, allowing the reverse DA to take place. As such, the endo product gets converted to the exo product.
