Radicals
If we want to start a synthesis on an alkane (a synthetically unhelpful starting material) what would we use?
Radicals!
so Br2 w/ hv or heat
How many pi bonds are in a double bond
in a triple bond?
double = 1 pi bond
triple = 2 pi bonds
What the heck is tBUOK?
Other reagents like it?
Big bulky base
steric hindrance leads to elimination on least stable side
DBN,DBU, tBUONa
What is the pka of Alcohols?
16
What are the three steps in radical halogenation called
(give super brief descriptions)
1.) Initiation (starts w/ no radicals, ends with 2)
2.) Propagation (Starts with a radical, ends with a radical)
3.) Termination (Starts with 2 radicals, ends with none)
How do we go from an alkyne to an alkene
straight reduction
H2 Lindlars Catalyst (Cis)
Na, NH3 (Trans)
What are the reagents used in Hydroboration Oxidation?
Other reagents similar?
1.)BH3, THF
2.)NaOH, H2O2, H2O
gives alcohol group with alkene (anti mark)
gives aldehyde with terminal alkyne (anti mark)
gives ketone with internal alkyne (both sides)
1.)R2BH or 1.)9-BBN
What degree alcohols (primary, secondary, tertiary) undergo...
1.) Nucleophilic substitution 1 and 2
2.) Elimination 1 and 2
SN2 = primary
SN1 = secondary, tertiary
E2 = primary
E1 = secondary, tertiary
Does Br2 w/ hv or heat add onto a least stable or most stable position?
(example, react w/ 2-methylpropane)
most stable! it adds onto the middle carbon.
(BONUS, what does adding HBr with ROOR to propene?)
You sure can.
1. Add Br2 w/ CCl4
2.) Add 2eq NaNH2 or NaH
What are the reagents in Oxymercuration Demurcuration?
1.)Hg(OAc)2, H2O, THF
2.) NaBH4
Gives markovnikov product w/o carbocation rearrangement
Tertiary
Why not use Cl2 instead of Br2 for any radical halogenation reactions?
Cl2 is NOT selective and reacts fast. (will give you 50/50 of most and least stable, see number 4 in this category)
Is this acetylide anion nucleophilic or electrophilic?
HCCH and HCC:-
The lone pair is a nucleophilic site.
I just saw this one and forgot it myself, what does
NBS w/ DMSO, H2O do?
NBS= Br2(radical halogenation)
DMSO, H2O = H2O
so it's a halohydrin formation (adding Br and OH)
Bonus does Br or OH go on more substituted carbon?
Draw the mechanism of 4-methylpentan-2-ol reacting with POCl3 and pyridine
Draw we shall
React cyclopentene with NBS and ROOR
Draw 1 initiation step
Draw 2 propagation steps
Draw 1 termination step
pKa of alkene and alkyne?
Alkene ~45
alkyne ~26
What's on the bottom of using KMnO4 with an alkene for hydroxylation?
H2O, cold, KOH or NaOH
What is always going to be the highest priority functional group (in this class)
It's in the name of the category