Orgo UMD Final Exam

Alkene plus _____ gives sin addition two OH groups

OsO4

NaHSO3 (or H2O2)

If you add an alkene and Br2, what happens?

What about when in H2O

anti addition.. Br to both sides. (tricenter intermediate) - so ends up being anti

When in H2O, OH adds to more substituted carbon instead of Br

What happens when you add an alkane with Br2 and heat

Radical reaction, Br adds to more substituted carbon

What is a good base to do E2 elimination reactions for less subsituted and more substituted

NaOEt

Turt Butyl

How would you synthesize an ether from an alkene

add ROH in acid (CH3OH, H2SO4), forms carbocation - rearangement

Add 1. Hg(OAc)2, ROH; 2. NaBH4 (Ether to more substituted side) - no rearangemnt

How would you add an OH to the less substituted side of an alkene

1. BH3; 2. H2O2, OH, H2O

How would you add an alcohol to the more substituted side

1. Hg(OAc)2, H2O

2. NaBH4 - no rearangement

H2O in Acid makes carbocation, so rearangement

if you have an alcohol, how would you make an alkyl bromide

HBr or PBr3 with pyradine

how would you get a double bonded O from an Alcohol

KMnO4 or PCC

how should you eliminate OH, for E1 and for E2

for E1 use acid/ heat

for E2 first toscelate with pyradine, then add turtbutoxide to eliminate

Bronsted Lowry vs Lewis

Bronsted deals wiht H+

Lewis deals with e-

Rule of Resiprocity

Strong aci gives up weak, stable conjugate base

hybridization

sp, sp2, sp3 duh

induction

where the electrons in a bond are pulled

Sin Trans and Cis vs Anti are the same thing

:)

activation energy symbol

Delta G with one of those double crosses

Gauche Interactions

non hydrogen groups neighboring eclipsed newman projection ... or posibly axial on a chair confomer

Meso

Asymetric carbon, but plain of symetry.. so there are stereoisomers but no enanteomer

chrial

You can switch 2 molecules and get an enantiomer

R vs S

Talking about stereochem... R is clockwise and S is counter clockwise

optically active

a chiral molecule that is not meso and you sould look this up actually then edit it

Markolnikov

Adds to more substituted side

Zaitzev

elimination towards more substituted side

Hoffman

elimination towards less substituted side

torsional strain

I think it has to do with eclipsed.. it's the strain that prevents a bond from twisting

Homotopic

switch 2 hydrogens and the molecule is identical to before

Enanteotopic

swithc 2 hydrogens and the molecule is an enanteomer of before

distereotopic

switch 2 molecules and you make a diastereomer of the molecue

pKa of HI

-10

pKa of HBr

-9

pKa of HCl

-8

pKa of Benzensulfonic acid (benzene - SO3)

-6.5

pka of Conj. acid of acetic acid (OH double bond and OH single bond both on carbon)

-6

pKa of Conj. acid of dimethyl ether

-3.5

pka of sulfuric acid (H2SO4

-3

pKa of Conj. acid of Ethanol (Ch3Ch2OH2+)

-2.4

pKa of hydronium ion (H3O+)

-1.7

pKa of Nitric Acid (HNO3)

-1.5

pKa of HF

3.2

pKa of Acetic acid (double bond O, OH, both to a carbon

5

pKa of hydrogen sulfide (H2S)

7

pKa of Amonium ion (NH4)

9.3

pKa of Hydrogen Cyanide (HCN)

9.3

pKa of phenol (benzene to OH)

10

pKa of methanethiol CH3SH

10.3

pKa of H2O

15.7

pKa of methenol (Ch3OH)

16

pKa of alkyne (CH3CCCH3

25

pKa of amonia (NH3)

36

pKa of H2

40

pKa of aldehyde

43

pKa of alkane

60

range of pkas (strong acid, weak acid, acid or base, very weak acid)

-10 - 0,

0 - 11,

11 - 20,

20 - 60

what spreads out a negative charge (stabalizes it)

1. electronegativity

2. size

3. resonance

what kind of acid would a strong nucleophile generate

a weak acid!!

Study your functional groups real fast

real fast

equation for degrees of unsaturation

2C - (H + hal) + N + 2

over 2

whenever there is a carbocation, what is the very next step you should check for

rearrangement

how to chose carbon chain

most carbons

if same amount, chose one with most substituents i think

prioritize alkene before substituents

How do you prioritize an asymetric carbon

first you see what atoms are connected

if 2 carbons, see what each is bonded too. add up atomic number of 3 attatchments

double bond counts as 2 carbon bonds

what is an easy way to find stereochemistry of dash and wedge if 4 is not on the dash

switch 4 with whatever is dash then do the opposite of what it says

IF you have a molecule with R, R, S, R, S what is the enantiomer going to look like

S, S, R, S, R

if doing sn2 wiht a strong vs weak nucleofile

sn2 is more favored for strong because its faster

what are 9 strong nucleophiles

I, Hs, OH, Br, H2S (ask kyra), RO, Cl, RSH, Nitriel

what are 3 weak nucleophiles

F-, H2O, ROH

What makes a good leaving group

conjugate base a strong acid

what solvent do Sn2 and E2 prefer? Why

polar aprotic solvent... aprotic nucleophile is not blocked

List 4 common polar aprotic solvents

acetone, DMSO, DME, DMF

litteraly say the flow chart for E1E2SN1SN2 in your head

primary - if bulky E2, if not SN2

secondary - if no charge base w/ heat E1 (sn1 minor), if no charge without heat Sn1 (E1 minor)

if charge and pKa conj acid <11 (LG or Nu, ask) SN2, if pkA > 11, E2

tertiary - good base makes E2

moderate nucleofile with heat makes E1 major, without heat pretty even

what would be best used for hoffman elimination

Turt butoxie

are elimination reactions stereospecific

YES!! .. draw LG and H that will be donating it's bond anti-perpuplanor on a newman projection... the two pairs with torsional strain will be cis on the alkene

What are some things that act as a nucleophile only

Cl, Br, I, Hs, Rs, H2S, RSH

what are some things that act as a base only

turt butoxide, H-

what are some strong nucleofiles

Ho, MeO, EtO all wiht minus

What happens if you put an SN2 / E2 reaction in a protic solvent

the reactants energy would be lower

what happens when you put E1 or SN1 in an aprotic solvent

raises the activation energy

Are Sn2 and Sn1 reactions endothermic or exothermic? what about E1 and E2

Substitution is exothermic

elimination is endothermic

is protonating an OH group exothermic or endothermic

apparently its exothermic according to my notes.. but f that all logic says exothermic so go with exothermic

what would be a good solvent to use if your trying to do anti halide addition with alkene

Cl2 and CCL4 (CCl4 and CH2Cl dissolves both alkenes and halogens)

What's so great about THF / what does it look like / when to use it

it is O with 4 carbons in a ring formation.. disolves H2O and organic compounds

use it when...

What does H3O plus do as a solvent

it does acid catalyzed hydration, however if concentrated will do elimination (reverse reaction)

ZnCL2 what does that do as aa solvent / when to use it

better protonator of OH then acid is

when should you use pyradine as a solvent

PBr3 and alkene

toscelation

if you have an alkene, what would add a halide to the more substituted side, less substituted side, and breifly describe mechanism

HBr for more (carbocation formed)

HBr in ROOR for less (radical)

if you have an alkene, what would do anti addition of 2 alkyl groups, what about one and an OH, what mechanism

Br2 / Cl2, Br2 in H2O, both tricentered intermediates

If you have an alkene, how would you add OH to a more substituted carbon

1. Hg(OAc)2, H2O, 2. NaBH4 (tricentered intermediate)

also using excess H3O+ would work

If you have an alkene, what would make an epoxide

RCO3H,

McPBA

find out difference

what is one way to make an ether

ROH with Acid

what kind of addition is H2/Pt

sin

what is a way to get anti OH onto an Alkene

make epoxide, using peroxy acid, then use H3O+ to break it anti into 2 OH

how would you add syn wo OH groups to an alkene

1. OsO4, 2. H2O2 (review mechanism)

also you could do KMnO4 and OH-, H2O (cold)(not as good)

How would you go about cleaving a double bond to make something like an aldehyde and stuff

O3 in DMS

KMnO4 in a strong acid (important to remember that this would make OH instead of leaving just H)

how would you turn a non terminal alcohol into a ketone, what about a terminal one into a carboxylic acid?

Na2Cr2O7 in H2SO4

same thing

how would you turn a terminal alchol into an aldehyde... what about into a carboxylic acid

aldehide is PCC, carboxylic acid is Na2Cr2O7 in H2SO4 or H2CrO4

how would you synthesize an ether from an alcohol

H3O+ and Heat

if you had a secondary alkyl halide in H2O, what would do an E2 reaction

KOH

let's say you have an alkyne, how would you add a double bonded O onto the more substituted carbon of that alkyne, getting rid of all other bonds

H2O

HgSO4, H2SO4 (adds to more substituted of alkyne)

1. HBr2 2. H2O2, H2O, OH- (for less substituted)

look up

how would you add 2 BR to the same carbon of an alkyne

excess HBr

What is something used to extend chain of an alkyne

NH2- makes an unsaturated side of an alkyne a nucleophile, then use Br-R to give an Sn2 substitution

if you have a tertiary alcohol or secondary alcohol, how would you do an elimination reaction

H3PO4 or H2SO4 and heat... it would remove OH group, make carbocation, then eliminate