反応例
11.1
アセタール化と関連反応
アセタール化
O
CH3
EtO OEt
CaCl2
H
CH3
EtOH
H. Adkins, B.H. Nissen,
Org. Synth., Coll. Vol. 1, 1 (1941).
H
61~64%
O
OEt
EtOH, HCl
H
Cl
OEt
34%
E.J. Witzemann, W.L. Evans, H. Hass, E.F. Schroeder,
Org. Synth., Coll. Vol. 2, 137 (1943).
O
+
HC(OEt)3
H
NH4NO3
OEt
EtOH
OEt
72-80%
rt, 6–8 h
J. A. VanAllan, Org. Synth., Coll. Vol. 4, 21 (1963).
O
H
O
HBr
p-TsOH
0 – 5 °C
HOCH2CH2CH2OH
Br
O
65%
rt, 8 h
J. C. Stowell, D. R. Keith, B. T. King, Org. Synth., Coll. Vol. 7, 59 (1990).
O
HC(OMe)3
HBr
H
CH2Cl2
0 °C, 2 min
CH3OH
0 °C, 10 min
CaCO3
0 °C, 1 h
MeO OMe
Br
H
52%
T. V. Lee, J. R. Porter, Org. Synth., Coll. Vol. 9, 643 (1998).
O
MeO
EtO
H
+
p-TsOH
HOCH2CH2OH
C6H6
reflux, 20 h
MeO
EtO
R. E. Ireland, D. M. Walba, Org. Synth., Coll. Vol. 6, 567 (1988).
O
O
H
94%
EtOOC
O
OH
+
EtOOC
Ph
OH
H
p-TsOH
EtOOC
O
cyclohexane
EtOOC
O
Ph
71%
B. Steuer, V. Wehner, A. Lieberknecht, V. Jäger, Org. Synth., Coll. Vol. 9, 39 (1998).
HO
OH
OH
+
O
TsOH
CH3CCH3
pet. ether, !
OH
O
O
87~90%
M. Renoll, M.S. Newman, Org. Synth., Coll. Vol. 3, 502 (1955).
O
HOCH2
+
Ph
CH2OH
O
HCl, H2O
CH2OH
Ph
CH2OH
O
73~77%
C.H. Issidorides, R. Gulen, Org. Synth., Coll. Vol. 4, 679 (1963).
H
HOCH2
CH2OH
O
Me2C(OMe) 2
O
TsOH, benzene, !
O
OH
+
65~74%
W.L. Howard, N.B. Lorette, Org. Synth., Coll. Vol. 5, 292 (1973).
HOH
HOH
HO
HO
HO
H
OH
CH3OH, HCl
OH
H
!
HO
HO
HO
H
OH
OCH3
H
49%
B. Helferich, W Schäfer, Org. Synth., Coll. Vol. 1, 364 (1941).
アセタール交換反応
MeO OMe
Me
Me
+
BuOH
TsOH
C6H5
58 °C
BuO OBu
Me
Me
75-80%
N. B. Lorette, W. L. Howard, Org. Synth., Coll. Vol. 5, 5 (1973).
MeO OMe
Br
Cl
HOCH2CH2CH2OH
Br
H2SO4
O
O
Cl
81-88%
140 °C, 8 h
D. L. Boger, C. E. Brotherton, G. I. Georg., Org. Synth., Coll. Vol. 8, 173 (1993).
Br
OH
+
P2O5
MeOCH2OMe
Br
O
78%
0 °C – 25 °C
7h
OMe
K. Tamao, Y. Nakagawa, Y. Ito, Org. Synth., Coll. Vol. 9, 539 (1998).
OH
OH
HO
OH
HO
SnCl2
+
MeO
OH
OMe
DME
reflux
1 – 1.5 h
O
O
HO
50-56%
C. R. Schmid, J. D. Bryant, Org. Synth., Coll. Vol. 9, 450 (1998).
アセタールの加水分解
MeO
O
OMe
H2SO4
H2O
20 h
90%
P. G. Gassman, J. L. Marshall, Org. Synth., Coll. Vol. 5, 91 (1973).
O
Me
H2SO4
O
Me
DMF
reflux
O
58-63%
H
M. R. Johnson, B. Rockborn, Org. Synth., Coll. Vol. 6, 312 (1988).
MeO OMe
cat.
H2SO4
H2O
CH2Cl2
0 °C, 3 h
OH
O
88-94%
R. Breslow, J. Pecoraro, T. Sugimoto, Org. Synth., Coll. Vol. 6, 361 (1988).
O
O
ジチオアセタールの合成
O
Ph
H
+
S
BF3•OEt2
HSCH2CH2SH
S
Ph
CHCl3
H
97%
rt, 2 h
Z.-J. Ni, T.-Y. Luh, Org. Synth., Coll. Vol. 9, 727 (1998).
ジチオアセタールの生成と脱硫
SH
HS
Raney Ni
S
BF3
O
S
81%
F. Sondheimer, S. Wolfe, Can. J. Chem., 37, 1870 (1959).
保護基としてのアセタール
HO2C
HO
CO2H
+ (MeO)2CMe2
OH
MeO2C
O
MeO2C
p-TsOH
C6H12
O
MeOH
reflux
+
O
85-92%
HOCH2
CO2Me
O
CO2Me
LiAlH4
CH2OH
NaOH
Et2O
reflux, 5 h
O
H2O
O
66%
E. A. Mash, K. A. Nelson, S. V. Deusen, S. B. Hemperly, Org. Synth., Coll. Vol. 8, 155 (1993).
MeOOC
O
OH
+
MeOOC
Me
OH
Me
BF3•Et2O
MeOOC
O
acetone
MeOOC
O
rt, 4 h
MeOOC
77%
MgBr
O
+
MeOOC
THF
rt – reflux
O
OH
Ar
Ar
Ar
Ar
O
Ar =
O
OH
82%
A. K. Beck, P. Gysi, L. L. Vecchia, D. Seebach, Org. Synth., Coll. Vol. 10, 349 (2004).