DAT ORGO - Alkenes and Alkynes

What directions should arrows point

away from electrons

Electrophiles

the ones getting attacked

Nucleophiles

the ones that do the attacking

Alkene addition reactions

Thing 2 goes on the carbon with less H+

Hyddrohalogenation

Where X is Cl, Br, or I

NO F

What does carbocation stability go by

If they are primary or secondary, and then resonance

Markovnikov products

Alkene addition product that comes from the most stable carbocation intermediate

1,2 hydride shifts

Hydrogen moves to carbocation next to it so that the product is attached to a more stable carbocation

1,2 methyl shifts

Methyl moves to carbocation next to it so that the product is attached to a more stable carbocation

Ring expansions

Like1,2 methyl reactions, but done to reduce ring strain

Acid catalyzed hydration

oxymercuration-demercuration reaction

acid cataylzed hydration, but it prevents rearangements

acid catalyzed alcohol reactions

Adding Halogens (X₂)

CL and Br ONLY

ALWAYS ANTI

Adding Halogens (X₂) and Water

H2O is signficantly more, so halogen anion cannot come through to the anti side

Adding Halogens (X₂) and ROH

ROH is signficantly more, so halogen anion cannot come through to the anti side

Is rearangement possible when adding halogens?

No, The halogen forms a ring

Hydroboration oxidation reaction

adds an OH to the anti-markovnikov carbon

always SYN BH3

Hydrobromination with peroxide

Adds a bromine to the antimarkovnikov carbon,

as long as HBr is added alonside a peroxide H2O2 or ROOR

Do radicals rearange like carbocations

no

Epoxidizing alkenes

adding a peroxy acid to an alkene leades to an epoxide

(MCPBA)

Adding nucleophiles to epoxides under basic conditions

The exception here is that the nucleophile comes in towards the least substituted part and the oxygen anion takes up an H+ from the environment THIS IS ANTI

Adding nucleophiles to epoxides under acidic conditions

The exception here is that the electrophile (the epoxide) grabs a H+, becoming positive. The nucleophile then comes in at the most substituted carbon.THIS IS ANTI

Anti-Dihydroxylation under acidic conditions

Anti-Dihydroxylation under basic conditions

Syn-dihydroxylation

OSO4 and peroxide

Ozonolysis of alkenes

Onzonolysis of alkenes - with peroxide

same thing as ozonolysis, but one of the hydrogens of the ch attached to the carbon turn into OHs

ozonolysis with KMnO4 - internal alkenes

when hot and concentrated, does the same as O3 and H2O2

ozonolysis with KMnO4 - external alkenes

Does the same thing as O3 and H2O2, cut turns the terminal carbon into CO2

Ozonolysis using HIO4!

First undegoes a Syn-dihydroxylation with OSO4

HIO4! then cuts it in half, much like O3

Kmno4 under non acidic, not hot conditions

acts the same as OSO4 and peroxide

Alkyne ozonolysis

two alkyne carbons turn into carboxylic acids

Alkyne ozonolysis With KMnO4

Does the same thing as O3, but NEEDS TO BE BASIC AND H3O AFTER

Terminal Alkyne ozonolysis

It will turn The non-terminal alkyne into carboxylic acid, and the terminal one into CO2,

much like KMnO4 under acidic conditions and terminal alkenes

Catalytic hydrogenation of alkenes

Hs end up on the same side

H2 and Pd, Pt, Rh, or Ni

Catalytic hydrogenation of alkynes - with intent to get an alkane

H2 and Pd, Pt Rh or Ni

Catalytic hydrogenation of alkynes - with intent to get an Z alkene

H2 and lindlar’s catalyst

Catalytic hydrogenation of alkynes - with intent to get an E alkene

Na or LI

with NH3 at low temps

alkene general reaction

can be turned into an alkane in excess, TYPICALLY ANTI

Hydrohalogenation on terminal alkynes

as with alkanes, the H’s go on the C’s with more H’s and the X’s go on the C’s with fewer H’s on them

Hydrohalogenation on Internal alkynes

unlike with alkanes, the H’s cannot go on the C’s with more H’s and the X’s cannot go on the C’s with fewer H’s on them. This leads to a forming of two different products

Alkyne Di-halogenation

CAN ONLY BE CL OR BR

Hydrobromination with peroxide with alkynes

Leads to the antimarkovinikov product

acid catalyzed hydration of alkynes

H2O, H2SO4, and HgSO4

Produce markovnikov product in terminal alkynes

Tautomerization

C=O OHs regularly turn into ketones

Antimarkovinikov oxidation/hydrobromination of alkynes

BH3/THF,

H2O2, OH, H2O

Turns into aldehyde

Alkylating alkynes

H atoms on the ends of terminal alkynes are sufficeintly acidic to be protenated by sodamide, this allows for reaction with a alkyl group (A BASE)

Alkylating alkynes with a ketone

Alkylating alkynes with an epoxide

The formation of alkynes from alkenes

First, a dihalogenation is needed, to form a dihalide along with sodamide (same reactant used for alkylations)

Kinetic product

product that forms the most stable carbocation intermediate

occur at -40 degrees celcius or lower

Thermodynamic product

more slow, moresubstituted alkene product

occur at 0 degrees celcius or higher

zatsiev rule

The alkane with the largest amounts of non hydrogens on its C=C double bond is the most thermodynamically stable alkene

Why do kinetic products form at low temperature

due to the fact that the stable carbocation intermediate is favored at lower tempeartures