Handout 1 Material Flashcards
(27 cards)
Is halohydrin addition syn or anti?
anti addition
Is hydrogenation syn or anti
syn addition
What are reagents for oxymercuration?
Hg(OAc)2 and NaBH4 for reduction
Is there an intermediate in oxymercuration and is the addition to the intermediate syn or anti?
Yes and it is anti
What are reagents for hydroboration?
BH3THF and then NaOH and H2O2
What are some advantages of 9-BBN
doesn’t react with carbonyls, air stable, stops after one addition, can be more regioselective
What do you use for dihydroxylation? And what is an associated problem?
OsO4 (osmium tetroxide) and it has associated toxicity.
What is upjohn modification?
Use NMO (n-methyl-morpholine N-oxide) to reoxidise osmium
Reagents for ozonlysis
O3/Me2S or can use PPh3
What happens during ozonlysis?
Break C=C make 2 new C=O
What 3 steps happen in ozonolysis of alkenes?
1,3-DP, then 1,3-retro DP, then 1,3-DP again (where 1,3-DP is 1,3-dipolar cycloaddition)
What do we use for epoxidation of alkenes?
MCPBA
Why is there no trans epoxide
C-O bond formation is concerted
Why do electron rich alkenes react the fastest?
reaction involves pi electron cloud attacking delta+ oxygen. R groups donate e- density.
Reagents for epoxide ring opening?
Nucleophile. Base common or NH2. Could use gringard also
How do you reduce an epoxide?
LiAlH4 or LiH3 works
Which nucleophile would you use in epoxide ring opening to generate salbutamol (anti-asthma drug)
an amine
How do you generate Z (cis) alkene?
Lindlar’s catalyst
How do you generate E (trans) alkene?
Dissolved metal reduction (example is NaNH3 and tBuOH)
Reagents for oxymercuration of alkynes?
Hg(OAc)2
What happens to final product of oxymercuration?
Tautomerises to a ketone
How does E alkene reaction from alkyne proceed?
Via sodium radicals
What isomer of alkene do you get from hydroboration of alkynes?
Trans isomer
Does hydroboration of alkyne stop at alkene?
No can go further to alkane
