CHEM 260 + 360 UTK Reactions Quizlet

Hydrohalogenation

Carbocation: yes

Regiochemistry: mark

Stereoselectivity: none

Reagent(s): HX = HCl, HBr, HI

- X added to more stable CC+ from alkene

- Possible 1,2 shift

*KNOW MECHANISM*

Hydration

Carbocation: yes

Regiochemistry: mark

Stereoselectivity: none

Reagent(s): strong acid (H2SO4) over H2O

- OH added to more stable CC+ of alkene

*KNOW MECHANISM*

Oxymercuration

Carbocation: no

Regiochemistry: mark

Stereoselectivity: none

Reagent(s): Hg(OAc)2 and H2O over NaBH

- OH added to more stable CC+ from alkene

Hydroboration

Carbocation: no

Regiochemistry: anti-mark

Stereoselectivity: syn

Reagent(s): 1. BH3 2. H2O2 and NaOH

- OH added to less stable CC+ from alkene

Halogenation

Carbocation: no

Regiochemistry: N/A

Stereoselectivity: anti

Reagent(s): X2 = Cl2 or Br2

- Anti addition of X to either side of alkene

KNOW MECHANISM

Halohydrin

Carbocation: no

Regiochemistry: mark (-OH)

Stereoselectivity: anti

Reagent(s): X2 = Cl2 or Br2 over H2O

- anti addition of OH to more stable CC+ of alkene

KNOW MECHANISM

Dihydroxylation

Carbocation: no

Regiochemistry: N/A

Stereoselectivity: syn

Reagent(s): OsO4 over tBuOOH

- syn addition of two OH on either side of alkene

Ozonolysis

Carbocation: no

Regiochemistry: N/A

Stereoselectivity: N/A

Reagent(s): 1. O3 2. SMe2

- addition of =O on both carbons the alkene was attached to

Hydrogenation

Carbocation: no

Regiochemistry: N/A

Stereoselectivity: syn

Reagent(s): H2 over M: M = Ni, Pd, Pt, Rh, Ir, Ru

- syn addition of two H on either side of alkene

SN2

Nucleophile replaces leaving group

Regiochemistry: anti with tertiary CC+

- Rate = k[substrate][nucleophile]

KNOW MECHANISM

SN1

Nucleophile replaces leaving group

Regiochemistry: no

- Rate = k[substrate]

KNOW MECHANISM

E2

Nucleophile acts as base to remove H and form alkene

- Big bases don't follow Zaitsev's rule

- Rate = k[substrate][nucleophile]

E1

Nucleophile acts as a base to remove H and form alkene

- Small bases usually follow Zaitsev's rule.Keep in mind situations where alkene has to form other way because LG and hydrogen must be anti/axial

- Rate = k[substrate]

Keto-enol tautomerization (not a reaction)

Enol groups (alkene with OH attached) are unstable and tautomerize into keto/aldehyde groups

In acidic conditions:

- Arrow from O of OH to C-OH bond, arrow from alkene to H of H-OH2^+, arrow from H-OH2^+ bond to O of OH2

- Arrow from O of H2O to H of C=O-H, arrow from attached O-H bond to =O

In basic conditions:

- Arrow from O of lone OH^- to H of attached OH, arrow from attached O-H bond to O of attached OH

- Arrow from O^- to =C-O bond, arrow from alkene to H of H-OH, arrow from H-OH bond to O of H-OH

Can go forwards or reverse (draw double sided arrow)

*KNOW MECHANISM*

Deprotonation

Carbocation: no

Regiochemistry: N/A

Stereoselectivity: none

Reagent(s): Bases = C, N, H ANIONS only

Alkylation

Carbocation: no

Regiochemistry: N/A

Stereoselectivity: none

Reagent(s): 1. Base = C, N, H ANIONS only 2. RX: R = primary or methyl and X = Br, Cl, I

Dehydrohalogenation

Carbocation: no

Regiochemistry: N/A

Stereoselectivity: none

Reagent(s): 1. Base = N anions only (3 equiv. for terminal alkynes; 2 equiv. for internal) 2. H3O+ (no 2nd step for 2 equiv.)

- Adds an alkyne to carbon(s) that the 2 Xs are attached to

- Turns alkane with X atoms into alkyne

Halogenation of alkyne (1 equivalent)

Carbocation: yes (no rearrangement)

Regiochemistry: mark

Stereoselectivity: anti

Reagent(s): 1 equivalent Cl2 or Br2

- Adds 1 X on both the alkyne carbons

Halogenation of alkyne (2 equivalent)

Carbocation: yes (no rearrangement)

Regiochemistry: mark

Stereoselectivity: anti

Reagent(s): 2 equivalents Cl2 or Br2

- Adds 2 X on both the alkyne carbons

Hydrohalogenation of alkyne (1 equivalent)

Carbocation: yes (no rearrangement)

Regiochemistry: mark

Stereoselectivity: anti

Reagent(s): HX = HCl, HBr, HI

- Becomes alkene and adds X to more stable CC+ and hydrogen to other carbon

Hydrohalogenation of alkyne (2 equivalents)

Carbocation: yes (no rearrangement)

Regiochemistry: mark

Stereoselectivity: anti

Reagent(s): HX = HCl, HBr, HI

- Becomes alkane and adds 2 X to more stable CC+

Hydroboration-oxidation (terminal alkyne)

Carbocation: no

Regiochemistry: anti-mark

Stereoselectivity: N/A

Reagent(s): 1. R2BH = (Sia)2BH or Cy2BH 2. H2O2, NaOH

- Adds a =O and hydrogen to terminal carbon (makes aldehyde)

Hydroboration-oxidation (internal alkyne)

Carbocation: no

Regiochemistry: N/A

Stereoselectivity: syn

Stereoselectivity: N/A

Reagent(s): 1. BH3 2. H2O2, NaOH

- Adds a =O to one alkyne carbon

Hydration of alkyne (terminal alkyne)

Carbocation: no

Regiochemistry: mark

Stereoselectivity: N/A

Reagent(s): 1. H2SO4, H2O 2. HgSO4

- Adds =O to inner terminal carbon of alkyne

Hydrogenation of alkyne (terminal alkyne)

Carbocation: no

Regiochemistry: N/A

Stereoselectivity: syn

Reagent(s): H2 over M = Ni, Pd, Pt, Ru, Rh, Ir

- Turns terminal alkyne into alkane

Hydrogenation of alkyne (Lindlar's Catalyst)

Carbocation: no

Regiochemistry: N/A

Stereoselectivity: syn

Reagent(s): H2 over Lindlar's catalyst

- Turns internal alkyne to (Z)-alkene

Hydrogenation of alkyne (hydroboration-protonolysis)

Carbocation: no

Regiochemistry: N/A

Stereoselectivity: syn

Reagent(s): 1. BH3 2. xs CH3CO2H

- Turns internal alkyne into (Z)-alkene

Hydrogenation of alkyne (metal reduction)

Carbocation: no

Regiochemistry: N/A

Stereoselectivity: anti

Reagent(s): M = Li, Na, K over NH3

- Turns internal alkyne into (E)-alkene

Radical halogenation

Intermediate: Radical

Regiochemistry:

- Cl2 low selectivity

- Br2 high selectivity

Stereoselectivity: none

- Reagent(s): X2 over hv (light) or heat

- Adds X to most (Br2) or least (Cl2) substituted

*KNOW MECHANISM*

Allylic halogenation

Intermediate: Radical

Regiochemistry: N/A

Stereoselectivity: selectivity for most substituted double bond in product

Reagent(s): NBS or NCS over hv

- NBS: X = Br

- NCS: X = Cl

- Adds X to most substituted allylic carbon

*KNOW MECHANISM*

Radical HBr addition (with peroxides)

Intermediate: Radical

Regiochemistry: anti-mark

Stereoselectivity: none

Reagent(s): HBr over peroxides = tBuOOtBu

- Radical goes to more substituted carbon of double bond, Br joins other carbon

Active metals reaction

Intermediate: none

Regiochemistry: N/A

Stereoselectivity: N/A

Reagent(s): M = Li, Na, K

- Turns OH into O^-

Hydride

Intermediate: none

Regiochemistry: N/A

Stereoselectivity: N/A

Reagent(s): NaH

- Turns OH into O^-

Hydrohalogen acid

Intermediate: none

Regiochemistry: REARRANGEMENT only possible if following CC+ can form:

- tertiary

- secondary benzylic/allylic

- tertiary benzylic/allylic

(reaction can still happen with primary, secondary, and tertiary)

Stereoselectivity: none

Reagent(s): HX: X = I, Br, Cl

- Turns OH into X

*With primary branched alcohols, simultaneous 1,2 shift can happen (methyl can move from most substituted to replace LG, leaving CC+ where the methyl left* - CANNOT occur with primary unbranched alcohols

*KNOW MECHANISM*

PBr3, SOCl2, SOBr3 reaction

Intermediate: no CC+

Regiochemistry: no rearrangment

Stereoselectivity: Inversion (SN2)

Reagent(s): PBr3/SOCl2/SOBr3

- Turns OH into X source and flips stereochemistry

- X source = PBr3, SOCl2, SOBr2 (image has typo)

*KNOW MECHANISM FOR PBr3*

Dehydration

Intermediate: CC+

Regiochemistry: unlike HX reaction, rearrangement will happen for all alcohols

Stereoselectivity: none

Reagent(s): H2SO4 over delta (heat)

- OH protonated, leaves, alkene is formed to CC+

*KNOW MECHANISM*

Nucleophilic Opening (Epoxide Opening)

SN2

Reagent(s): NON-POOR Nu^- (NH3/C^- anion) OVER H2O/EtOH, etc.

OR

1. LiAlH4 2. H2O (H^- is Nu^-)

NEED: EPOXIDE -> Nu-R-OH

Nu^- ATTACKS LEAST SUBSTITUTED

Acid Catalyzed Opening (Epoxide Opening)

SN2

Reagent(s): POOR Nu^- OVER STRONG ACID

OR

STRONG ACID (HX)

NEED: EPOXIDE -> Nu-R-OH

Nu^- ATTACKS MOST SUBSTITUTED

POOR Nu^- WILL PROTONATE/DEPROTONATE

USE ALREADY PROTONATED POOR Nu^- (CH3OH2+)

Grignard (Basic)

Reagent(s): Mg OVER Et2O (aprotic solvent/no H-bonds)

NEED: R-X -> R-MgX

MUST PROTECT AN EXISTING OH on R-X WITH SILYL ETHER

R-MgBr/R-Li Reactions (Epoxide Opening)

VERY STRONG BASES

-MUST PROTECT EXISTING OH WITH SILYL ETHER

Reagent(s): MUST HAVE R-MgBr OR R-Li AND PROTON SOURCE (H3O+)

Nu^- ATTACKS LEAST SUBSTITUTED (UNLESS CATALYZED BY ACID)

SAME AS Nu^- OPENING

Carbonyl under Acidic/Basic Conditions

Acidic: R-C=O -R -> R-C-OH+ -R (causes resonance)

Then Basic attacks C, causes Resonance and balance

Basic (Strong Nu^-): R-C=O -R -> R-C-O^- -Nu - R (causes resonance)

Then O^- attacks acid, causes balance

Carbonyl Reactions With Carbon Nu^-

CREATES C-C BONDS

- Grignards

- Organolithium

- Alkyne anion

- Hydrocyanation (equilibrium arrows)

Reagent(s): ANY ABOVE + MUST HAVE PROTON SOURCE (H3O+)

NEED: C=O -> OH + new C-C

Carbon Nu^- attacks C of C=O, kicks up double bond to lone pair, oxygen protonated

Hydride Reduction

Reagent(s): 1. LiAlH4 2. H3O+ OR 1. NaBH4 2. ROH/H2O

H^- Nu attacks C=O

LiAlH4 = more reactive, less selective

NaBH4 = less reactive, more selective

C=O -> C-OH

H2/Rh

Reagent(s): H2/Rh

Reduces alkene, LEAVES C=O ALONE

Making Carboxylic Acids

Oxidation of Primary -OH with Jones' Reagent

Grignards + CO2

Haloform

Hydrolysis of Carboxylic Derivatives

Reduction of Carboxylic Acids

Hydride Reduction: 1. LiAlH4 2. H3O+

- C.A. -> -OH

Diazomethane: H2C=N^+=N^-

- C.A. -> Ester + N2

Beta-Keto Acid: Heat

- Beta-Keto Acid -> Ketone + CO2

- Gets rid of a single C.A.

Nucleophilic Addition to Carboxylic Acids (Recap)

Carbon Nu: (Grignard for example = MgBrR)

- C.A. -> Carboxylate + R (steals H)

- Acid/Base because C.A. is not as E^+ as ketones/aldehydes and C^- is EXTREMELY STRONG

Hydrogen Reduction: 1. LiAlH4 2. H3O^+

- C.A. -> Alcohol

Nitrogen Nu: H2NR

- C.A. -> Carboxylate + H3N^+R

- Acid/Basebecause C.A. is not as E^+ as ketones/aldehydes and N^- Nu is VERY STRONG

Oxygen Nu: ROH, Acid

- C.A. -> O=C-OR + H2O

Carboxylic Acid Derivative + Grignard

Reagent(s): 1. 2 equiv. MgXR 2. H3O^+

Ester

- O=C-OR -> HO-C-R

- Ketone intermediate attacked by grignard again then H3O^+ to make alcohol

Acid Halide

- R-X -> R-HO-R

- R added to C-OH

MAKES AN ALCOHOL