Orgo Radicals Quiz

Heat or light

Main conditions needed for homolytic cleavage (creation of radicals)

T

T/F: The stability of a radical follows the same pattern as carbocation stability

Hyperconjugation

Radicals are stabilized by ….

Benzylic Radical (Draw out!)

Allylic Radical

NBS/NCS

Common bromide/chloride radical source

AIBN

Source of this radical

Radical Coupling

Abstraction

Addition (to alkene)

3 types of radical reactivity

Radical coupling

What is this type of radical reactivity?

Abstraction

What is this type of radical reactivity?

Sigma

Abstraction is often a reaction between a radical and a [pi/sigma] bond

Radical Addition to Alkene

What is this type of radical reactivity?

Initiation

Forms the 1st radicals in a reaction

Propogation

Stage when the desired reaction occurs + regenerated the reactive species

Termination

Quenching of the radical species

Regeneration of reagents

Creation of product

New side product

Ways for a radical rxn to be quenched/terminated

I2 < Br2 < Cl2< F2

Order of rate of reaction with halogen gases

An iodide radical is relatively stable due to its larger e- cloud —> lower reactivity —> Slower rxn

Why is a reaction with iodide so slow?

Br2

Which is more selective?: Cl2 or Br2

Chlorination

Is chlorination or bromination faster?

1 carbon away

A benzylic alkyl group will add a halide…

Draw the product(s) of this reaction

Draw the product(s) of this reaction

Anti-markovnikov

Draw the mechanism + product(s) of this reaction. What is this product called?

Radical initiator

Peroxide is considered a …

sp²; planar; loss of stereochemical information

The carbon with the radical is sp^# hybridized and …, leading to….

Draw the 2 types of peroxides

Draw the reaction between (PhCO2)2 with HBr

Hint: Produces Br radical - how?

Possibility of e1 reactions

Draw the reaction: Radical hydrogenation of alkynes using Na or Li metal w/ HN3

What do we need to worry about with this reaction?

Hint: Results in highly basic byproducts

Draw the reaction of HSnBu3 (organotin) with light

Draw the product(s) of this reaction

AIBN, Higher temps (60^oC)

What can be used to activate HSnBu3 to form a radical? What is that reaction? What conditions does it require?

Forming C-C bonds

What is/are the product(s) of this reaction? What are the products useful for?

Draw the products of these reactions

Draw the product(s) of this reaction

The addition of gem-dimethyls results in a faster ring closure reaction

due to higher steric hinderance favoring ring closure (& other intramolecular reactions)

What is the Thorpe-Infold Effect?