Orgo Exam 3 Definitions

Activation Energy

Energy difference between reactants and transtition states

Addition Reaction

When 2 reactants add together to make a single product with no "leftovers"

Bond dissociation Energy

Amount of energy needed to break a bond

Carbocation

A positive charged carbon

Electrophile

An electron loving species that has positive polarization

Elimination reaction

hen a single reactant split into 2 products

Endergonic

A reaction that absorbs energy and has a G>0

Exergonic

A reaction that releases energy and has a G

Endothermic

When DeltaH is positive and energy is absorbed

Exerthermic

When DeltaH is negative and energy is released

Enthalpy Change (deltaH)

Measure of change in total bond energy during reaction

Entropy Change (deltaS)

Measure of change in amount of molecule randomness/freedom

Gibbs free energy

Energy change that occurs during a reaction

Heat of reaction

Same as energy deltaH

Inititation Step

First step of a radical reaction that creates radicals

Nucleophile

A substance that is "nucleus-loving" with a negative polarization

Polar reaction

process that involves unsymmetrical bond breaking and making

Propagation

Middle step of radical reactions where the radical reacts with a stable molecule

Radical

A neutral species that contains and odd # of e- and a single unpaired e-

Radical reaction

Process that involves symmetrical bond breaking and bond making

Reaction coordinate

Horizontal axis that represents the progress of the reaction from beginning to end

Reaction intermediate

a substance that only transiently exissts during the multistep reaction

Reaction Mechanism

Overall description of how a reaction occurs

Rearrangement reaction

When a single product undergoes a reorganization of bonds

Substitution reaction

When 2 reactants exchange parts to make 2 new products

Regiochemistry

study of preference for a direction of bond formation

Termination step

Final step of radical reaction where 2 radicals continue to form stable molecules

Transition state

When a structure of maximum energy is reached

Allylic

A carbon atom that is directly attatched to a c-c double bond

Carbanion

A carbon that is an anion

Gilman Reagent (LiR2Cu)

Lithium diorganocopper compounds

Grignard Reagent (RMgX)

Alkylmagnesium halides formed in either ether or THF

Organometallic

A molecule that contains a carbon, orgaic group, lower metal atom

Anti-periplanar

The geometry in which the H + x are on oppositie sides of molecules

Bimolecular

When 2 molecules specifically a nucleuophile + alkyl halide take part in a steo

Deuterium isotope effect

when a C-H bond is weaker than C-D bond

E2 reaction

A elimination, bimolecular reaction that happens when alkyl halide is w/strong base

Hofmann (anti-zaitsev) products

The less substitued/less stable alkene formed as major

Leaving group

The group displaced by the incoming nucleophile

Nucleophile sub reaction

Steps that involves sub of 1 nucleophile by another

Periplanar

When all 4 reaction atoms (H, C, C, LG) lie in the same plane

rate determining step/rate limiting step

The transition state that has higher energy than others and is slower

2nd order reaction

Reaction in which the rate relies dependently on the [] of 2 species

Sn2 reaction

A substitution, nucleophile, bimolecular reaction

Syn periplanar

The geometry in which the H + X are on the same side of the molecule

Zaitzeus rule/ Product

Elimination reactions generally give to more stable alkene product (alkene with more alkyl substituents)