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Epoxidation with Peroxy AcidsR
morereactive
OH
OCO O
‡
RCO3H
Freccero, M.; Gandolfi, R.; Sarzi-Amadè, M.; Rastelli, A. J. Org. Chem. 2000, 65, 2030.Singleton, D. A.; Merrigan, S. R.; Liu, J.; Houk, K. N. J. Am. Chem. Soc. 1997, 119, 3385.
more likely
Epoxidation under Basic ConditionsM O
t-Bu
O
MeOt-BuOOHTriton® B
O
MeO
O
O
OO
H THFO
OH
t d li h lf h i
Triton® B = benzyltrimethylammonium hydroxide in H2O
trans-decalin half-chair
O
MeO
OO
OO
H
1,3-diaxial interaction
Grieco, P. A. et al. J. Am. Chem. Soc. 1977, 99, 5773.
transition metal-catalyzedHenbest epoxidationEpoxidation of Allyl Alcohols
transition metal catalyzed epoxidation
relative rateVO(acac)2
Henbest epoxidation
O
VO(acac)2t-BuOOH
1.00
OH OH
O >200
O
t-Bu
V O
OO
RO
Hoveyda, A. H.; Evans, D. A.; Fu, G. C. Chem. Rev. 1993, 93, 1307.Henbest, H. B.; Wilson, R. A. I. J. Chem. Soc. 1957, 1958.Sharpless, K. B.; Michaelson, R. C. J. Am. Chem. Soc. 1973, 95, 6136.
O
Early Examples of Asymmetric Epoxidationof Allyl Alcohols
Yamada, S. et al. J. Am. Chem. Soc. 1977, 99, 1988.
Sharpless, K. B. et al. J. Am. Chem. Soc. 1977, 99, 1990.
Essence of Sharpless Asymmetric EpoxidationOHEtO C
[O]slow
CO2Et
OHEtO2C
HO
R2 R1
R3 OH2 1
D-(–)-diethyl tartrate(unnatural)
[O]R3
R
HR2 R1
R2 R1
R3 OHO
Ti(Oi-Pr)4t B OOH
[O]fast
R R
R3 OH
R
R2 R1
O
t-BuOOH
CH2Cl2
R2 R1
R3 OHH
R3 OHO
[O]R H
R
CO2Et
OHEtO2C
HO
Johnson, R. A.; Sharpless, K. B. In Catalytic Asymmetric Synthesis, 2nd ed.; Ojima, I. Ed.; Wiley-VCH: New York; 2000.
CO2EtHO
L-(+)-diethyl tartrate(natural)
Katsuki, T.; Sharpless, K. B. J. Am. Chem. Soc. 1980, 102, 5974.pSharpless, K. B., et al. J. Am. Chem. Soc. 1987, 109, 5765.
Katsuki, T. In Comprehensive Asymmetric Synthesis, Vol II; Jacobsen, E. N.; Pfaltz, A.; Yamamoto, H., Eds.; Springer:Berlin; 1999.
(+) DETBnO OH
OBnO
BnO OH
OBn
Sharplessepoxidation
L-(+)-DET OBnClCH2SO2O
OB
single isomer
OBnClCH2SO2Oepoxidation
D-(–)-DETBnO OH
OBn
OBn
ClCH2SO2O
O
OBnClCH2SO2O
single isomer
Kajimoto, T.; Wong, C.-H. Tetrahedron Lett. 1995, 36, 8247.
Kinetic Resolution of Racemic Allylic Alcohols
OH
H
OH
H
OH
H
O O
+
(+)-DIPTTi(Oi-Pr)4
CH2Cl2–20 ºC20 C
erythro threo98 : 2(S)
kfast/kslow = 104OH
H
OH
H
OH
H
O O
+
(+)-DIPTTi(Oi-Pr)4
CH2Cl2
fast slow
H H HCH2Cl2–20 ºC
erythro threo38 : 62(R)
Sharpless, K. B., et al. J. Am. Chem. Soc. 1981, 103, 6237.
Combination of asymmetric synthesis and kinetic resolution can deliver products with very high ee.p y g
OH
OHTi(Oi-Pr)4 (1.1 equiv)t-BuOOH (2.0 equiv)(–)-DIPT (1.3 equiv)
O major
CH2Cl2–25 ºC
80–85% yieldOH
iy
Ominor
0.5 h: 88% ee
1 h : 94% ee
1.5 h: >99.3% ee
Schreiber, S. L., et al. J. Am. Chem. Soc. 1987, 109, 1525.
Catalyst Structure and Proposed “Loaded” Catalyst
O ORO
ORE OR
TiO
TiO OR
O
OO
E
OR
ROHO
t-BuOOH
TiO ORO
OR
E
E O
TiO
TiO O
OO
E E
t-BuRO
Finn, M. G.; Sharpless, K. B. J. Am. Chem. Soc. 1991, 113, 113.Katsuki, T. In Comprehensive Asymmetric Synthesis, Vol II; Jacobsen, E. N.; Pfaltz, A.; Yamamoto, H., Eds.; Springer:Berlin; 1999.
Asymmetric Epoxidation of Unfunctionalized Olefins
O OO
OO
O
O
O(30 mol %)
OXONE®, K2CO3
Ph Ph
OOXONE , K2CO3
CH3CN/dimethoxymethane0.05 M Na2B4O7 10H2O of aqueous 94% yield0.05 M Na2B4O7 10H2O of aqueous
Na2(EDTA) (4x10-4 M) solution
OXONE® = 2KHSO5 · KHSO4 · K2SO4
94% yield95.5% ee
Shi, Y. et al. J. Am. Chem. Soc. 1997, 119, 11224.
Na2(EDTA) is used to prevent trace-metal-catalyzed peroxide decomposition.
Mn–Salen-Catalyzed Asymmetric Epoxidation
N NMn
H H
Ph
O O
t-Bu t-Bu
t-But-Bu Cl
(5 mol %)Ph Ph
O
(5 mol %)NaOCl (aq.)
CH2Cl2
81% yield92% ee
Jacobsen, E. N. et al. J. Am. Chem. Soc. 1991, 113, 7063. Jacobsen, E. N. et al. J. Am. Chem. Soc. 1990, 112, 2081. Katsuki, T. et al. Tetrahedron Lett. 1990, 31, 7345.
Dihydroxylation with Osmium Tetroxide
catalytic reaction
Milas, N. A.; Sussman, S. J. Am. Chem. Soc. 1936, 58, 1302.
acceleration by tertiary aminesy y
Criegee, R.; Marchand, B.; Wannowius, H. Liebigs Ann. Chem. 1942, 550, 99.
OMe
Asymmetric Dihydroxylation (AD)
N
OAc
OMe
Sharpless, K. B., et al. J. Am. Chem. Soc. 1980, 102, 4263.
PhPh
PhPh
OHN (1.1 equiv)
OsO4 (1.1 equiv)
toluene
LiAlH4
OHtoluene
90% yield83.2% ee
NNO O
N
H
N
H
(1 mol%)K OsO (OH) (0 2 mol%)
N N
MeO OMeSharpless, K. B., et al. J. Org. Chem.
1992, 57, 2768..
PhPh
PhPh
OHK2OsO2(OH)4 (0.2 mol%)
K3Fe(CN)6 (3 equiv), K2CO3 (3 equiv)CH3SO2NH2 (1 equiv)
t-BuOH/H2OOH
2
>80% yield>99.5% ee
RR
Catalytic Cycle
+ L
R
OOs
O
O
OOs O
OO
O
R
HO
R
OH
R
+ L OOO
L
HO OH + L
organic
aqueous
2 HO2 H2O
Os
OHO OH
2–
Os
OHO O
2– 2 HO
aqueous
Os
OHO OH
Os
OHO O
2 HO 2 H2O2 Fe(CN)6
3–2
2 Fe(CN)64–
Two Proposed Mechanisms
Hoffmann, R., et al. J. Am. Chem. Soc. 1986, 108, 1867.Corey, E. J., et al. J. Am. Chem. Soc. 1996, 118, 11038.
Sharpless, K. B., et al. J. Am. Chem. Soc. 1997, 119, 1840.Houk, K. N.; Sharpless, K. B.; Singleton, D. A., et al. J. Am. Chem. Soc. 1997, 119, 9907.
Click Chemistry: Diverse Chemical Function from a Few Good ReactionsFunction from a Few Good Reactions
H h C K lb M G Fi d K B Sh l *
Angew Chem Int Ed 2001 40 2004
Hartmuth C. Kolb, M. G. Finn, and K. Barry Sharpless*
Angew. Chem. Int. Ed. 2001, 40, 2004.
“Nature is a matchless creator of C‐C linkages and we propose leaving the tough job of C‐C bond synthesis as much as possible to her.”
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