Organic Chemistry Test 3 Vocab

Orgo 1 Test 3 Vocab WM

Addition Reaction Number of products and reactants

2 Reactants 1 Product

Elimination Reaction Number of products and reactants

1 Reactant 2 Products

Substitution Reaction Number of products and reactants

2 Reactants 2 Products

Rearrangement

1 Reactant 1 Product

Polar Mechanisms

Electrons move in pairs, Curved Double headed arrows, unsymmetrical/ heterolytic cleavage

Radical Mechanisms

Electrons move individually, Curved arrows single barbed, Symmetrical/homolytic Cleavage

When is Carbon negatively polarized?

When Carbon is bound to a metal

When is Carbon positively polarized?

When Carbon is bound to something electronegative.

What are Nucleophiles?

Lewis Bases; will form a new bond by donating a pair of electrons to a positively polarized atom.

Nucleophiles can have what charge?

Neutral or Negatively charged

What are Electrophiles?

Lewis Acids; can form a bond by accepting a pair of electrons.

Electrophiles can have what charge?

Neutral or Positively Charged.

Large K_eq means?

Products are favored.

Small K_eq means?

Reactants are favored

K_eq = 1

Reactants and Products are equally favored

Equation for Gibbs Free energy

ΔG = ΔH- TΔS

ΔG

Gibbs Free-energy; net overall change of energy in a reaction; exergonic <0: endergonic > 0

ΔH

Enthalpy; net Bonding energy in a reaction; Exothermic < 0: Endothermic > 0

ΔS

Entropy; net Molecular randomness in a reaction

Transition state

Transient structure of maximum energy in a reaction

Intermediate

local energy well in a reaction

Hammond Postulate

The structure of a transition state resembles the structure of the nearest stable species.

Basicity

H⁺ Transfer favorability, thermodynamic concept of ΔG^o

Nucleophilicity

Rate of e^- pair donation, A kinetic concept of ΔG^t

Radical Reactions ignore what?

Stereochemistry is ignored in radical reactions because they are on an sp² hybridized planar structure.

Initiation of Radical Reactions

Heat or Light breaks the weak bond between 2 atoms forming radicals which cause self sustaining chain reactions

Propagation of Radical Reactions

Chaining of Radical substitution and Radical addition reaction

Termination of Radical Reactions

A rare event where 2 radicals come together resulting in no remaining radicals.

Nucleophilic Addition

Nucleophile forms new sigma bond to electron poor atom which breaks the pi bond

Electrophilic addition

Electrons from a pi bond act as a nucleophile to form sigma bond to an electrophile breaking pi bond leaving an atom with a positive charge

Coordination

Lewis base donates a pair of electrons to an electron deficient Lewis Acid forming a new sigma bond

Coupling

sigma bond formed between two radicals

Bimolecular elimination

AB: forms a bond to a proton the electrons from the H-C bond move to form a pi bond to a neighboring atom and then they bond to a LG on the neighboring C leaves

Nucleophilic elimination

LP of electrons from a more electronegative atom moves to form a new pi bond to a less electronegative atom while a bond to that atom breaks in one step

Electrophilic elimination

electron from a C-electrophile bond move to form a pi bond between carbon and a neighboring atom. The electrophile attaches to a separate species that is not electron deficient.

Proton transfer

Base forms a new bond to a H atom while the H-acid bond breaks

Bimolecular Nucleophilic Substitution

Lone pair of nucleophile does back side attack on 1* or 2* C-LG. Transition state has partial C-Nu and C-LG bonds. Stereochemistry inverted.

Unimolecular Nucleophilic Substitution

Spontaneous dissociation of a 3* halide and alcohols, allylic and benzylic halides to form a carbocation intermediate reacting with nucleophile. Full or partial loss of stereochemistry.

Heterolytic bond dissociation

sigma bond broken, both electrons from bond go to one atom involved in original sigma bond.

homolytic bond dissociation

sigma bond broken one electron remains with each atom involve in original sigma bond

Unsaturated hydrocarbons

restricted rotation around C-C bond, planar orientation

Z,E system

Z = same side of highest priority; E = opposite side of highest priority r group

Small rings double bonds must be _

Cis

Large rings (cyclooctene+) stable with

trans isomer

How to calculate the maximum number of stereoisomers

2^n where n = #stereocenters+double bonds

Terpenes

natural product with 5 carbon atoms

1-2 shifts

Hydride or alkanide migration moves 1 bond over to make a more stable carbocation

Stereoselective rxn

a stereoisomer is formed in preference to all others

Hydrohalogenation

Markovnikov, not stereoselective, and carbocation intermediate

Hyperconjugation

Hyperconjugation is the stabilizing interaction that results from the interaction of the electrons in a σ-bond (usually C-H or C-C) with an adjacent empty or partially filled p-orbital or a π-orbital to give an extended molecular orbital that increases the stability of the system.

Halogenation of Alkenes

Markovnikov, Anti stereochemistry, bridged halonium ion intermediate

Halohydrin Formation

halogen is on less substituted, and alcohol is on more substituted carbon, Anti, and Markovnikov

Oxymercuration-Reduction

Adding water across a double bond alternative, no 1,2 shifts, anti, Markovnikov, 1. Hg(OAc)2, H20 2. NaBH4

Hydroboration

1. BH3+THF 2. H2O2, NaOH

Anti-Markovnikov, Syn, concerted

Osmylation

Syn stereochemistry, no regiochemistry, concerted process, 1. OsO4; 2. NaHSO3, H2O

Ozonolysis

Breaks Pi and sigma bond of alkene, forming ketone and ether 1. O3 2. (CH3)2S; or ketone and carboxylic acid 1. O3 2. H2O2

Catalytic Hydrogenation

Syn; no regiochemistry, could change regiochemistry; requires Pd, Pt or Ni catalyst adds hydrogen to both sides

Alkene stability

tetrasubstituted > monosubstituted; and Sp²-Sp³ bonds are stronger than Sp³-Sp³ bonds

Radical stability

3* radical is more stable than a 1* radical, 1* benzylic radical is less than a 3* radical

Asymmetric Alkenes in radical halogenation

produce a major product with more substituted alkene

ROOR

peroxide, good radical indicator

Oxidation reactions

Decrease Electron density on Carbon

Reduction reactions

increase electron density on carbon

Oxidation level formula (w/ same number of carbons)

#C = #(C-O)+#(C-N)+#(C-X)-#(C-H)