hydroboration-oxidation electrophile ng pd az h r on itiverson.cm.utexas.edu/courses/310m/lecture...
TRANSCRIPT
-
Hydroboration-Oxidation
H
C
C
C
H
H
H
H
H+ H B
Products
Summary:
Regiochemistry:
Stereochemistry:
Example:
1. BH3
R
R
transition state
2. H2O2 / HO
(R = H or alkyl group depending on how far
reaction has progressed)
(Chemist opens flask and adds new reagent)
2. H2O2 / HO
ng RElectrophile azpDon it transit
stateNucleophile
Breaking
Not responsible Rfor l
H HH
mechanism H BR
H d d C H H i teI I 1 H c c c H SymH H H 13GHz H H H
H more substitutedH and B addto the sane facecarbon
HOT less substituted carbon ofthe alkene
The pi bond of the alkene attack theLewis acid 13 atom at the same timea new bond forms between C and H
4memberedringtransitionstatenon Markovnikov PPG'Iekotonifovhatule
Syn
yki 3 Mikitaq Latif't
4oRacemic
LeusubstitutedC atom
-
OH
TF 1 Not ChardHzsoyca IE
MOH
Oxidation reaction net lossof electrons
a reaction involving loss ofbonds to It atoms and orincrease in number of
T1 bonds or bonds to 0atoms
Reduction reaction net gainof electrons
a reaction that involvesan increase in bonds toH atoms or a decreasein IN bonds or bonds to0 atoms
-
reduction
cHzCH CHzCHIEH Hat
reduction doxidationOH OH O 01 oxidation is i
c Hz CH CH cHzC c OH
y reductionvicinal diol 1,2 dialbnext to each other
-
OsO4 Partial Mechanism
Os
O
OO
O
OsO4
H H
H3C H
A cyclic osmate ester
2. NaHSO3 / H2O
(Chemist opensup flask)
Product
2. NaHSO3 / H2O
1. OsO4
Example:
Summary:
Regiochemistry:
Stereochemistry:
Ozzy Osbourne Reactionof
AHEeE Oc Los
gl e u
HeO
It Racemic
Not responsiblefor mecha B
AHsCaE.O.H
I Raceae
Hear HH
Mechanism involves acycle Os mate ester 0atoms add to same face synN A 0 atms on both C atonsSyn
put OHii OH ThicHz1 if't t ds.ioRacemic
-
Products
Ozonolysis Partial Mechanism
O
O
O O
O
O O
O
O O
O
O
Ozone contributing structures
O
O
O
H
H
H3C
H3C
Malozonide
Rearrangementin two steps
2. (CH3)2S
Ozonide
(Chemist opensup flask)
1. O3
2. (CH3)2S
Example:
Summary:
Regiochemistry:
Stereochemistry:
Breaks C c
i EMakemake s
pa
pbadi
c ibad HEE c'off
HE
Replaced C C with 2 GO
O OIl Il
Hz Ct Utz H C H Agin itaHf t.lt
-
O
Oo
Link to register for Global Run:
https://eventdog.com/a/eventpage.php?eID=31750
Code:
IversonRUNS2020
-
Hydrogenation: H2 with Pt°, Pd°, Ni°
H H H H
CC
H3C
H
H
H
H H H H
H H HH H
Products
H H H H
Pt°, Pd°, Ni° metal particle surfaceH
HH
H
H2 / Pd°
Example:
Summary:
Regiochemistry:
Stereochemistry: