Addition Reactions Flashcards
What is needed for hydrohalogenation? What are the steps? What kind of addition?
- HX
- Pi bond attacks H and Halide attacks +
- Markovnikov
What reagent is needed for hydrohalogenation to be antimarkovnikov addition?
ROOR
What are the steps of hydrohalogenation with ROOR?
- ROOR breaks into 2 OH radicals
- Radicals propogate HX into H2O and X radical
- X radical attacks more substituted side
What is needed for hydration? What are the steps? What kind of addition?
- dilute H2SO4
- Proton transfer, carbocat rearrangement, water attacks +, water attacks intermediate to make H3O+
- markovnikov
What reagent is needed to make hydration an antimarkovnikov addition reaction?
BH3*THF/H2O2, NaOH
What is needed for catalytic hydrogenation? What are the steps? What kind of addition?
- H2/PT
- Metal surface holds down substrate and pi bond breaks
- syn addition
What is needed for halogenation? What kind of addition?
- BR2/CCl4
- antiaddition
What is needed for halohydrin formation? What are the steps? What kind of addition?
- X2/H2O
- OH adds to more substituted carbon and X adds to the other
- Antiaddition
What is needed for anti-dihydroxylation? What kind of addition?
1.mCPBA/2. H3O+
Antiaddition
What are the steps of anti-dihydroxylation?
- H attacks C
- Pi bond attacks O
- Bond between Os attacks bond over
- Epoxide initiates proton transfer
- Water attacks carbon to attack + on O
- Watr attacks again to make H3O+ and diols
What is important to check for with anti-dihydroxylation? How do you check?
Meso compounds
Look for opposite configurations
What reagent is needed for oxidative cleavage? What happens in the products?
O3/DMS
All pi bonds break into aldehydes/carbonyls
What is needed for syn-dihydroxylation? What kind of addition?
OsO4 (catalytic)/NMO — synaddition
KMnO4, NaOH/cold — antiaddition
What is needed for alkyne formation? What are the steps?
1.xs NaNH2/2. H2O
- NH2 attacks beta H
- Double bond forms
- LG leaves
- Repeats to form alkyne
What is needed for alkylating terminal alkenes? What is the process?
- NaNH2 (can be xs)/ 2. Alkyl Halide
- NH2 attacks H
- lone pair attacks alpha carbon
- LG leaves
What is needed for alkyne reduction? What are the products?
H2/Lindlars — cis alkene
Na/NH3 (L) — trans alkene
H2/Pt. — alkane
What are the steps of alkyne reduction with Na/NH3?
- Na radical attacks triple bond
- single radical and double radical form on opposite sides of triple bond
- double radical attacks H on NH3 and bond breaks
- Na radical attacks single radical
- double radical attacks NH3
What is needed for the markovnikov addition version of hydrohalogenation of alkynes?
- xs NaNH2/NH3 / 2. H2O 3. HBr
What is needed for the antimarkovnikov version of hydrohalogenation of alkynes?
- xs NaNH2/NH3 / 2. H2O 3. HBr, ROOR
What is needed for the hydration of alkynes?
H2SO4, H2O/ HgSO4 — carbonyl will be on more substituted end
- 9-BBN/2. H2O2, NaOH — carbonyl will be on less substituted end
What are the steps of enol-keto tautomerization in the presence of an acid?
- Proton transfer
- Resonance
- Proton transfer
What are the steps of enol-keto tautomerization in the presence of an acid?
- Proton transfer
- resonance
- proton transfer