1,5-h shift
DESCRIPTION
文献汇报. 1,5-H shift. 何玉萍 2010-11-06. R=CH3, X=- 45h yield 91% R=CH3, X=CH2 90h yield 95% R= OCH3 , X=- 20h yield 77% R= OCH3 , X=CH2 20h yield 90%. 其中类似 CF3 的强吸电子基团是必不可少的. 均不能发生类似的反应. - PowerPoint PPT PresentationTRANSCRIPT
1,5-H shift
文献汇报
何玉萍2010-11-06
R=CH3, X=- 45h yield 91%R=CH3, X=CH2 90h yield 95%R=OCH3, X=- 20h yield 77%R=OCH3, X=CH2 20h yield 90%
T.L., D. N. Reinhoudt, 24, 3923,1983.
N
RO
CF3
n-BuOH
refulx O
NX
H CF3
X
N
RO
CF3O
NX
H CF3
XN+
RO-
CF3
XN+
R O-
XH
H
CF3H
1,5-H shift
O
N
O
OR
N
其中类似 CF3 的强吸电子基团是必不可少的
均不能发生类似的反应
N
CF3
N Ph CH3 118℃5d
H3CH3C
NH
CF3H
N
CF3
N Ph CH3H3CO
n-BuOH
n-BuOH 118℃OR MeCN 81℃
X
14% 66%
X
√
1,R1=CH3, R2=CF3
2,R1=H, R2=H3,R1=H, R2=CH3
4,R1=H, R2=C6H5
Lawesson reagent
D. N. Reinhoudt
R2 可以不必是强吸电子基团
R1
N
O
R
PH3COS
PS
S
SOCH3 R1
N
S
R
N
S
H R2
HR1
tol uene115℃
N
O
H R2
HR1
R1
N
O
RR1
N
S
R
N+
R
S-
H
H1,5-H shift
N+
R
S-
R1
R1H
S
N
H R
H
Mechanism
Tetrahedron.1984,4309-4312
Solvent Yield
5a Toluene 54%/32%
1-butanol cis 74%
5b X
5c X
7a toluene 3d X
1-butanol 44%/42%
MeCN/ZnCl2 47%/12%
7b 1-butanol 6dMeCN/ZnCl2 3d
X
toluene/ZnCl2 11%/26%
7c tolueneCH3COOH 12d
X
9 1-butanol 10dMeCN/ZnCl2 3d
X
10 1-butanol 67%
11a11b11c
1-butanol 2htoluene 35h
82%78%84%
D. N. Reinhoudt, JOC, 49, 2, 1984.
N
Mechanism
总结 :1, 溶剂效应 ( 极性溶剂更容易促进反应 )2,lewis 酸可以促进反应3
4 任何可以稳定 1,5- 偶极的基团都可以促进反应
N N
O
> >
1,6H shiftN+
C- CH2R2
NX
R1
H
R2
H
H
X
R1
stereo-
mutation
N+
C- R1
X
CH2R2
N
R1R2H2C
5a R1=R2=COOEt, X=_
7a R1=CN, R2=Ph, X=_
7b R1=CN, R2=Ph, X=CH2
H
N
RR
XH
H
H
N+
RR
XH
H
a
[1,6] H
b
[1,5] H
C-
N+X
H
RRH
C-
N+X
H H
RR
[1,2] H
NX
RR
10, R=COOEt, X=_
11a, R=CN, X=_
11b, R=CN, X=CH2
11c, R=CN, X=O
b
与 5 不同
D. N. Reinhoudt, Tetrahedron Letter, 1984, 25, 19, 2025.
N
NC OHH
H
NC X
N N+
C-NC
XH
N+
Y-
NC
H
NC
(CH2)4Y
H
X=OAc,OTS,Cl
acetyl chloridep-Toluenesulfonyl chlorideDMF 50℃
3a
Synthesis, 2005, 2161.Synthesis, 2007, 2872.
Daniel Seidel, Org. Lett. 2009, 11, 129.
rt
illustrate for the first time that such a reaction is amendable to enantioselective catalysis.
Dainel Seidel, J. Am. Chem. Soc. 2009,131,13266
the first example of a catalytic enantioselective hydride shift/ring closure reaction cascade
the first example of a organocatalytic enantioselective hydride transfer/ring closure reaction cascade
J. Am. Chem. Soc. DaeYoungKim, 2010, 132, 11847
Daniel Seidel, J. Am. Chem. Soc. 2008, 130, 416
Sames, J. Am. Chem. Soc. 2005, 127, 12180.
无杂原子
Sames, Org. Lett. 2005, 7, 5429.
O HO
EE
lewis acid
rt O O
EE
H
[1,5] H
O+
EE
H O M-
M
C-O 形成
1 , BF3.Et2O 是催化该反应最好的 lewis acid2 ,所得产物不一定全是螺环,如 15 , 17. 但需要更强的 lewis acid TiF4 。3 , ketone 19 也可以参与类似的反应。只是还未找到更为有效的催化剂。
OO
E
E
2
OO
E
9
OO
22
E E
OO
23 20
O
O
EE
1
O
O
E
8
O
O21
EE
O
O22
O
19
Me Me
ArMe
O
Me Me
ArMe
-6.79 -2.33 +2.42 +0.13 +1.21
O
Me Me
ArMe
Me Me
OAr Me
Ar=4-(MeO)C6H4
4 : 96
30% mmol BF3.Et2O
CH2Cl2,rt, 5h
DFT caculation
No reaction Low yieldexcellent yield
O
E
PtXn 5mol%
MeCN, 120℃ O
EUnactivated teminal alkynes
Lewis acid activation of the terminal alkyne and the subsequent hydride transfer
Sames, J. Am. Chem. Soc. 2009, 131, 16525.
PtI4 more electrophilic and more accessible to the alkyne
Greater hydride PtI4NoReationK2PtCl
苄醚
Deuterium Labeling Studies and Proposed Mechanisms
H
O Ph
DD
H
O Ph
DD
I4Pt
O+Ph
D
H-I4Pt
I4Pt
H
D
DPhO
D
D
Ph
O
PtI4
Ph
D D
O+Ph
D
D PtI4-
I4Pt
D
DPhH
Path B
vinylideneformation
Path A
alkyneactivation
[1,6] H [1,5] H
C-C bondformation
C-C bondformation
[1,2]H
Sames, Org. Lett. 2009, 11, 2972.
less active need stronger activation
the aryl alkyl ethers were less reactive in comparison to the dialkyl ethers
no reaction was observed in theabsence of catalyst under these conditions
Akiyama, Org. Lett. 2010, 12, 1732.