Chapter 20 - Dienes, Conjugated Systems, and Pericyclic Reactions

Beer Lambert Law

Beer Lambert Law

The ________, A is the connection between absorbance, concentration, and the length of the sample cell (cuvette)

Carbonyl groups

________, like C "C double bonds, can participate in conjugation.

Ultraviolet

________ and visible spectral data are displayed as absorbance (A) vs wavelength, where absorbance is determined as the log base 10 of the ratio of (I0 /I), where I0 is the intensity of light irradiating a sample at a specific wavelength and I is the light passed through the sample.

dienophile

A(n) ________ is a molecule having a double or triple bond that interacts with a diene, and the cyclic result is commonly referred to as the Diels- Alder adduct.

Pericyclic reactions

________ take place in a single step and involve a transition state with a closed loop of orbitals.

Diels Alder reaction

The ________ is aided by the presence of electron- withdrawing groups on one reactant (typically the dienophile) and electron- releasing groups on the other (usually the diene)

4 Addition

1, ________ to butadiene produces the dominating product at higher temperatures under thermodynamic control, since the double bond of the 1, ________ product is more substituted and hence of lesser quality.

function of wavelength

The molar absorptivity (extinction coefficient) as a(n) ________ is unique to a molecule and is determined by the functional groups included inside the molecule.

ultraviolet spectrum

In the near ________, the p S p* transition for unconjugated alkenes is frequently too high in energy (wavelength too short)

Diels Alder reaction

In the ________, conjugated dienes combine with specific types of molecules that have double or triple bonds to generate two new s bonds and a ring structure, which is an example of a 4 1 2 cycloaddition process.