ian fleming’s molecular orbitals and organic chemical ... · z-conformer e-conformer s-trans...
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Ian Fleming’s Molecular Orbitals and Organic Chemical Reactions
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(( ))))(( 22)) 2211-- ** ,,2211 ff jj
,, ((11 zzaacc,, ((11 ))))(( zzaaccjj
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,,((11((
,,** (( 33,,(( 22::(( 1122 33,,((
2211 ,,(( ,, //
S(Synmetric)
A(Antisynmetric)
A(Antisynmetric)
S(Synmetric)
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C=C C=C- C=C(( //((11(( ,,((11((
S(Synmetric)
A(Antisynmetric)
S(Synmetric)
A(Antisynmetric)
S
A
S
A
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//// // ((
S(Synmetric)
A(Antisynmetric)
S(Synmetric)
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22//((,,11
C=C C=C- CH=O(( //((11((
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X-substituents C=C C=C- OCH3
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C+ C+- CH=O
π-stabilization
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ff
C-C+H
C=CH+
2211 //((11** ((11,,11**
2211 22 ((11,,11**
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ff
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C-C+C
C=CC+
2211 //((11** ((11,,11**
2211 22 ((11,,11**
ff
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// ,, // 22)) //2233 2233 11((
energy level
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,, //22
((33 // ,,2211
typical C(sp3)-C(sp2): 1.522Åtypical C(sp3)-C(sp3): 1.538Å
2211 //((11** ((11,,11**
2211 22 ((11,,11**
δ
δδδ
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)) 11 ,, ,,2211 (( (( 22)) 22 ,,2211,,11
,, (( ,,)) 11 **11(( (((( ::((,,11 33(((( 11**(( ((11
22 2211 // (( 22 (( ,, ,,2211 22)) //(()),,11
(( 22)) 22 ,,2211
H more stableless stable
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11 (( ,,2211 22)) 22 ,,2211 ::,, UU 2211 ,, 2211**(( 11UU 11 2211
,, **(( ((2211// ::,, (( // ,,2211
,, (( ,, ((
22 22)) (( // ,,2211,, **(( ::,, 22//(()),,11
22 (( //((
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//,, //(( ((11(( ** //22::(( ,,11** (())))(( 2211 ,,2211 //22:: // ,,11** WW 2211
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22 (( ,,//,, (( 33(( 2211-- ** ,,2211::,, UU 11 22 2211
// **(( ((11(( ** //22::(( ,,11** (())))(( 2211 11,,2211 WW 2211
vs
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11 ,,33(( ,,33// 11 33// 11 ,,**2211 //11,, 22**((11 22
) 2 2) (3(3 2) (3
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Anionic negative (Fluorine) hyperconjugative interaction between anionic center and C-F bonds at the β- position
C-F
C-F
anti
σ*
σ
n
orbital interaction
carbanion
Ion-dipole interaction between anionic center and C-F and CF3 bonds (inductive and field effect)
δ +
δ −
δ +
δ −
ion-dipole interaction
C-C bond shortening C-F bond elongation charge delocalization to F atom
No C-CF3 σ * hyperconjugation??
((//(( 22 ,, ,,11 (( ,,2211
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11((** ,, (( 33(( 2211-- ** ,,2211 22)) WWBB 2211::,, //2211(( 33 ,, ((//(( 2211
22 (( //((
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33 (())(( ((11 ,, // 22 ,,((11 ,,2211 22)) (( 22 //,, 22 **((11 //2211(( 33 ,,11 ,,33(( ,,33// 11 22 ((11 22 //,, WWBB 2211 ,,11 22 22)),, // 11 (( 22 ,, // 2211))22 ((
,, // 2211))22 (( (( 22 ,, // 2211))22 ((
(( 22 1122 (( ,, (())))((
33 (())(( ((11 (( ))22 ** (( 22 ,,((11 ,,2211
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))// 22 22 (( 1122//
(( 22 (( // //22 ,, ((
,, //.. // ,, == //22 ((11 11((
22 //(( 2211))22 (( ::,, anti-Periplanar Orientation** (( 22 ,,((11 ,,2211
,, // 2211))22 ((
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anti-periplanar
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anti-periplanar syn-coplanarvs
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s-trans s-cisZ-conformer E-conformer
,,((11((
more stable more stable
repulsivemore stable
Cyclic lactones are more reactive comapred with open-chain esters.
anti
1122 (( ,, (())))((//2211(( 33 ,, 22)) 22 **((11 22 ,, 11 ,,
33(( ,,33// 11 22 WWBB 2211 22)) ** 22 33
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33// ,,11 :: (( ,, //(( ((::,, ,, ,,11 2211 ,, (( ,,11** (( ((11(( **,,(( 22)) ((
,,11 (( ,,11** 33 22 ,, //
33// ,,11 (( ,, ((11 (())))(( 2211 (( ))22////22::,,11**2211))22 ,,2211 (( ,,//,, ,,
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Ian Fleming’s Molecular Orbitals and Organic Chemical Reactions
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aa
aa aacc
aa PP ee
aa eeCC
aa aa PPOO
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!Peter!Sykes!( )!!
( )!
!Peter!Sykes!( ),!! ( )!
;!!5 (1984/01)(1996/03) (2010/1/22)
!
Robert!B.!Grossman!( ),!! ( )!
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Modern'Physical'Organic'Chemistry''Eric'V.'Anslyn'(),''Dennis'A.'Dougherty'()''
:'1104 '( 10,786)
Univ'Science'Books;''illustrated'ediKon (2005/07)
Advanced'Organic'Chemistry:''Part'A:'Structure'and'Mechanisms'Francis'A.'Carey'(),''Richard'J.'Sundberg'()''
:1199 ( 5,678)'Springer;'5th'ed.'2007.''Corr.'2nd'prinKng (2007/6/13)
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::
. . 2 1 . . 2 1 ::
+ . 1- ::
:2 1 2 1 :
:-1 2 -1 2 :
::
- (1 1 1 ) . ::
() . .
-
3 -
-
I
2 ) 3(
I
2 ) 3(
3 ( - -
3 ( ) - - - -
3 ( 3 -) - 3 -)- -
solvent(polar(effect
sp3 carbon
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CH3O- Ph2CH2
K
CH3OH Ph2CH-
Solvent K
H2O 10-18
gas-phase 1011
AA 22 3322 33 AA
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CH3-OH 291 kJ mol-1
H-Br 366 kJ mol-1
CH3-Br 291 kJ mol-1
H-OH 499 kJ mol-1
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!""! !!749!kJ!mol*1
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!""
!!!!!!790!kJ!mol*1
) )( Δ!H!o =!!749!–!790!!=!!*!41!kJ!mol*1
-1' 31 1 ,
-1' 31 1 ,
+ ( C
) C)( C
-1' , 1 31
7BE F CB F7F
Δ G = Δ H -TΔ S
0 E B G -=7B C 7BE F CB F7F C 4 79F CB
Δ H
Δ Ho
radicals(遷移状態)
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) (
) TS
(Reac(on+Coordiate)
(Reac(on+Intermediate)
+(Gibb’s+Ac(va(on+Energy)
(Organic Reaction Mechanism)
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))
((
((
( )
-
))
11 22 --
)) II -- CC((
-
((
((
-
(( 2211 3322 // (( [[vvAA
early TS late TS
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hh ee hh ee nndd
LL hh ee mm hh ee mmdd
hh DDii oo((
)) )) oo((
LL oo ,, --..
cc dd jjCC
gg ll oo
AA:: ))TTII gg ll EE
BB)) dd BB
aa
HH MM ff
A + B A-B
-
B
FF
F
N
H
H
H
B N
H
HH
FF
F
C
HH
H
H C H
HH
H
trifluoroborane BF3
methyl cation CH3 +
(isoelectronic to BF3)
hydride methane
ammonia NH3 Lewis acid-base complex
sp2 boron
sp2 carbon sp3 carbon
sp3 boron
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ssIIuu
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]]hhmmIImmbb
ttxxiill
ww dd ww ddxxiill
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]]hhmmIImmbb
ttxxiill
ww dd ww ddxxiill
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(( 11 ,, (( 11 22)) ,,
22)) (( 11 22)) ,, 22)) (( 11 ,,
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xxiill tt xxiill CCoo XX
22)) 22)) xxiill ee pp?? qq mmppxxiill CCoo XX
22 ,,(( dd ggrrCCyy EE OO FFnn MMNN 22)) HH OO
WWkk II LL
ssZZPPTT SSRR??
jj mmbbxxiill AA
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Nucleophilic Substitution Reactions of Alkyl Halide (
Substitution Nucleophilic Unimolecular (two-step reaction)
Substitution Nucleophilic Bimolecular (one-step reaction)
carbocation intermediate
Transition State
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( 1 ) )1 ) ( 1 ) )
) )1 )
1 )
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Example: SN1 vs E1
2-bromo-2-methylpropane
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Hyperconjugative Stabilization in tert-Butyl Cation
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Elimination Reactions of Alkyl Halide (
Elimination Unimolecular (two-step reaction)
Elimination Bimolecular (one-step reaction)
carbocation intermediate
Transition State
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( ) ) ) 2 )) 2 )
TransitionState
TransitionState
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SN2
SN2
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E2
E2
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21 - 4 , 4 4 21
1 4
, 4 ,
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Highest Occupied Molecular Orbital (HOMO)
Lowest Unoccupied Molecular Orbital (LUMO)
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E
E
E
E
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SiMe3
SiMe3
E E
E
SiMe3
E
( -
(
( - - 3 β− σ
))
( )
(
hyperconjugation of β-C-Si σ bond
[ ]
Frontier MO interaction
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-D 4 B60 7C4 017 7E0 7 5 0 1 0 71D 7 σ ) 3 C σ ) 3
Δ(C-Si)
Δ(C-C)
σ
σ
σ
σ
) 4 6D
7(
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