Organic Chemistry 1: strong/weak nucleophiles + bases - E1/E2 + Sn1/Sn2 reactions

-CN

strong nucleophile

weak base

-OH

strong base

strong nuclophile

-OCH3

strong base

strong nucleophile

CH3OH

weak nucleophile

weak base

-N3

strong nucleophile

weak base

-Cl

strong nucleophile

weak base

-Br

strong nucleophile

weak base

t-BuO

Strong or Weak Base?

Strong or Weak Nucleophile?

always does which rxn?

strong base

weak nucleophile

E2 b/c bulky base

-OCH2CH3

strong base and strong nucleophile

-OR

strong base

strong nucleophile

-I

strong nucleophile

weak base

-SH

strong nucleophile

weak base

-SR

strong nucleophile

weak base

NR

strong nucleophile

all right base

PR

strong nucleophile

weak base

Strong nucleophiles/weak bases that favor Sn2?

hint: there are (7)

CN

N3

Cl

Br

I

SH

SR

NR

PR

strong bases/strong nucleophiles that are able to do:

E2 or SN2

hint: there are (2)

-OH

-OR

strong bases & strong nucleophiles can do...?

E2 or SN2 or both

what do we look for when we determine if a strong nucleophile and a strong base will do:

E2 or SN2 or both?

E2=tertiary

Sn2=primary

E2 and Sn2 if secondary

what type of solvent is Acetone?

Aprotic

what type of solvent is DMSO?

Aprotic

what type of solvent is DMF?

aprotic

what type of solvent is acetonitrile?

aprotic

what type of solvent is ether?

aprotic

what type of solvent is THF?

aprotic

name all of the aprotic solvents:

hint: there are (6)

acetone

DHF

DMSO

THF

acetonitrile

ether

what does it mean to be protic?

can form H-Bonds

what rxn is Solvolysis associated with?

sn1

aprotic strong nucleophile trend

up and to the left

protic strong nucleophile trend

down and to the left

what are the key things to remember about an SN2 rxn?

requires a strong nucleophile

does a backside attack

inverts stereochemistry

3>1>2

what type of solvent is used in SN2

prefers aprotic

it can do protic

Sn2 rate law

rate = K [nucleophile][electrophile]

Sn1 breif explanation

leaving group leaves on its own first

carbocation forms

rearrangement can occur

can do strong or weak nucleophile

can produce a racemic mix

Sn1 solvent used

protic

Sn1 rate law

rate= K[electro}

zatizev

remove hydrogen from the B-carbon with the least H's (most substituted)

key components for E2

1 step

follows Zaitsev

usually forms an alkene

H must be anti peri planar from leaving group

favors strong bases

3>2>1

E2 rate law

Rate=K [nucleophile][electrophile]

E2 solvent

prefers aprotic

can do protic

E2 rxn prefer strong/weak bases?

strong bases

what're the key aspects of an E1 rxn?

leaving group leaves 1st

forms a carbocation, rearrangement is possible

weak/strong base comes in and takes an H following Zaitsev's rule

3>2

E1 prefers what type of solvent?

protic

things to remember about:

t-Buo

bulky base

always does E2

anti Zaitsev

conjugation

what is it?

how does it relate to stability?

what does it use?

when the double bond formed from E2 is one single bond away from another double bond

gives stability

uses antizatizev

what is a Reasonable Cationic Intermediate (RIC)?

tertiary, secondary, or resonance stabilized carbons

Sterically Hindered Nucleophile

Tertiary Nucleophiles

sterically hindered electrophile

tertiary alkyl halides

Exception: sterically hindered electrophile

neopentyl halides

In what rxn mechanism should you pay close attention to H2O?

why?

E1

instead of acting as a nucleophile, H2O acts as a base

Define: steric hindrance

interference by bulky groups that slow a reaction or prevent it from occurring