EE - cpp.edu
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CHM 4220 OUJDQLF S\QWKHVLV, CDO PRO\ PRPRQD, DU. LDXULH S. SWDUNH\ CKDSWHU 8 ± OUJDQRPHWDOOLF S\QWKHVLV 18-EOHFWURQ RXOH (RU EAN, EIIHFWLYH AWRPLF NXPEHU, RXOH) E[amples of TransiWion MeWals Used in S\nWhesis MeWal Sc Ti Zr V Cr Mo W Mn Fe RX Os Co(I) Rh(I) Ir(I) Ni Pd PW CX(I) Zn(II) “d´ elecWronV 3 4 5 6 7 8 8 10 10 10 elecWronV needed p EE , # sure - s !y÷q . → → 15 14 13 12 11 10 !0 8 8 8 Rhd ) % : : " : " ( ¥÷÷J::i . O coordinately unsaturated o . r÷÷÷¥;ru÷ : + ( ] - +3 O %÷ . Could dbt 4e-CUx2)t 8 e- ( NHzx4)= 18 e - coordinating saturated
Transcript of EE - cpp.edu
CHM 4220 Organic Synthesis, Cal Poly Pomona, Dr. Laurie S. Starkey Chapter 8 – Organometallic Synthesis
18-Electron Rule (or EAN, Effective Atomic Number, Rule)
Examples of Transition Metals Used in Synthesis
Metal Sc Ti Zr V
Cr Mo W
Mn Fe Ru Os
Co(I) Rh(I) Ir(I)
Ni Pd Pt
Cu(I) Zn(II)
“d” electrons 3 4 5 6 7 8 8 10 10 10
electrons needed
p
EE,
#sure - s !y÷q.
→
→
15 14 13 12 11 10 !0 8 8 8
Rhd)
% : : ":" ( ¥÷÷J::i.O
coordinatelyunsaturatedo. r÷÷÷¥;ru÷:
+ ( ]- +3
O %÷.
Could dbt 4e-CUx2)t 8 e- (NHzx4)= 18 e-
coordinating saturated
Examples of carbon/hydrogen ligands
8.1 Analyzing Transition Metal Complexes
“Charge” on metal? Electron count on metal? Is it coordinatively saturated (i.e. 18 electrons)?
Grubbs catalyst
P M M
m⑤ Icu, into Mto :B to gf carted
A allyl of":c -=o : mm:
"
"m'
no @ =. ¥4 !'carbonmonoxide m④
pass o : : ÷! %.
?TptohrdD -n "
at:Din Codd
• Ru orCt . I
¥ "÷÷÷÷¥÷÷÷÷:"H , +6 - 4 → +2
a:O*
(ng
&. . .-N - Cll)
⑥ read Te"
8.2 Organometallic Reaction Mechanisms
Ligand Exchange
Oxidative Addition – results in +2 change in oxidation number
Reductive Elimination – results in -2 change in oxidation number
f.some
numberCHIEN : qwgcindsO
. .
"
O (solvent)
printer
- Z
→ 00d.addition
Pda) -pdldqox.no.oxidation
✓red - eliminator
G- A
⑥ .
RWMgoy.ro.
refutation←bonds
!
new0 A 00 I
Migratory Insertion
Beta Elimination
Describe each step, determine Rh oxidation state throughout:
{HOg-T
m O-
O
Z
MA bk
k
dimwit alhinerdivatnt
migratoryinsertion
Transmetalation
Transmetalation is involved in cross-coupling reactions
Transition Metal-Mediated Synthetic Transformations
8.3 Carbonylation and Decarbonylation
a hydroformylation reaction
convert aldehydes to alkanes (RCHO → RH), or acid chlorides to alkyl halides (RCOCl → RCl)
I CO④O i
- -
O a← O
*
*
④aLagaan:* 0*7 fondant
¥0•
(m) If
origin's cm migration•
c, •w
migratory2
insertion
8.4 The Heck Reaction
Example:
8.5 Pd-Catalyzed Cross-Coupling Reactions Stille Reaction
Example:
halim alkene gnewcebond• •
gp's
⑦-
th
Feme④ we
oxiaddn'
O
eliminator0
ringworm
o rin : .
.
.
O
••
refineries oxaddn'
OI0
a0
transmutation
Suzuki-Miyaura Reaction
Use a Suzuki-Miyaura Coupling Reaction to achieve the following transformation:
HBb d
"b BB
i
" Bg . . . ⇒
A RBIZz
ABB" b Ipp, /ppy,Boy pdCMhd4NaOH
O O
he
8.6 Olefin Metathesis Reactions
Cross-Metathesis
[2+2]cycloaddition
alkene #1reactant
metathesis product
CH2R1
LnM CH2
LnM
CH2
CH2
R1
CH2
CH2
MLn
R1
alkene #2reactant
LnM CH2
R1
H2CR2
R2
[2+2]cycloaddition
alkenebyproduct
retro[2+2]
retro[2+2]
R2
R1
Use a Cross-Metathesis Reaction to achieve the following transformation:
MeO
HO
eugenol
MeO
HO
CO2Me
q9
alkene O ⑥⑥payloads)
o
'
9
KHZ CHECK•④
boo! =p
|¥'m Ian ←
come
←
HECK
Ring-Closing Metathesis (RCM)
CH2 CH2
M
CH2
H2C CH2
CH2 M
MH2C
dienestartingmaterial
cyclic alkeneproduct
volatileethyleneproduct
catalytic cycle continues
• •• •
origins creutz
I am}•
•
O O
o o
Polymerization
I
O O✓
O O O O O
ph onWed btw ← bond
• *
*
