Unit 5: Organic Reactions & Curved Arrows

thermodynamics

the study of the relative energy levels of reactants and products

kinetics

the study of the rate (“speeed”) of a reaction

enthalpy

the measure of the energy exchanged between the system and its surroundings

exothermic

reactions where heat is released; the reactants have more energy than the products

endothermic

reactions where heat is required; the reactants have less energy than the products

entropy

the measure of disorder associated with a system

ΔG < 0

an exergonic reaction where the reactants have more energy than the products

ΔG > 0

an endergonic reaction where the products have more energy than the reactants

rate-determining step

the slow step of a reaction

activation energy

the energy needed to get over the “hump”/get the reaction going

intermediate

a short-lived, high energy molecule that is no longer a reactant but not yet a product; no partial bonds are present; appears as local minima on a graph

transition state

a high energy stsate that cannot be isoated where bonds are in the process of being broken/formed; partial bonds are present; appear as local maxima on a graph

1. substitution

2. elimination

3. addition

the 3 categories of organic reactions

substitution

1 of the 3 categories of organic reactions where 1 group is replaced with another group; in this, the leaving group is the group being replaced and the nucleophilie is the group doing the replacing

elimination

1 of the 3 categories of organic reactions where a pi bond is formed between two atoms and two other atoms are leaving

addition

1 of the 3 categories of organic reactions where a pi bond is removed and 2 new atoms are added

1. nucleophilic ttack

2. loss of a leaving group

3. proton transfer

4. rearrangement

the 4 main categories for the mechanistic steps of organic reactions

nucleophile

an electron-rich center that will react with a (partial) positive charge; typically will have a negative or partial negative charge

electrophile

an electron-deficient center that will react with a (partial) negative charge; typically will have a positive or partial positive charge; “electron lover”

nucleophilic attack

1 of the 4 main categories for the mechanistic steps of organic reactions where electrons move from an atom to a molecule and form a new bond

loss of a leaving group

1 the 4 main categories for the mechanistic steps of organic reactions where a bond is broken between an atom and a molecule and the electrons are placed onto the atom

proton transfer

1 the 4 main categories for the mechanistic steps of organic reactions; an acid-base reaction

rearrangement

1 the 4 main categories for the mechanistic steps of organic reactions where a carbocation is stabilized by the movement of a hydrogen or methyl group being moved to either add more R groups to the carbocation or allow it to be stabilized via resonance

hyperconjugation

the stabilization of an atom by neighboring alkyl groups; carbocations undergo rearrangements for this to occur

hydride shift

when a hydrogen moves in a rearrangement to stabilize a carbocation via hyperconjugation; only ONE curved arrow is needed to show this!!!

methyl shift

when a methyl group moves in a rearrangement to stabilize a carbocation via hyperconjugation; only ONE curved arrow is needed to show this!!!