Biomedical Engineering Reference
In-Depth Information
OBn
1. Tf 2 O, TTBP
CH 2 Cl 2 , -78°C
2.
OBn
OBn
BnO
O
OBn
BnO
O
OBn
O
O
O
Ph
Ph
Ph
O
O
O
O
DDQ
83%
O
O
O
O
OMe
OMe
HO
PMBO
PMBO
BnO
BnO
BnO
HO
OBn
S
O
O
Ph
Donor 1
OMe
α/β
= 1:10
BnO
89%
OBn
O
PMP
O
O
BnO
S
O
Ph
OBn
Tf 2 O, TTBP
CH 2 Cl 2 , -78°C
OBn
BnO
O
O
OBn
Ph
O
O
O
O
PMP
O
O
OMe
O
(α/β
= 1:9)
BnO
80%
BnO
OBn
BnO
O
OBn
BnO
O
OBn
Ph
1. AcOH, CH 2 Cl 2 (70%)
O
O
O
O
O
OMe
HO
BnO
2. n -Bu 2 SnO, PhMe
3. BnBr, CsF
87% (over 2 steps)
BnO
Donor 1 , Tf 2 O
TTBP, CH 2 Cl 2 , -78°C
OBn
OBn
BnO
O
OBn
BnO
O
O
OBn
Ph
Ph
O
O
O
O
O
O
O
O
OMe
(α/β
= 1:7.5)
PMBO
BnO
BnO
70%
OBn
BnO
O
OBn
OBn
BnO
O
OBn
Ph
Iteratio n
O
Ph
O
O
O
O
O
O
O
O
OMe
BnO
PMBO
BnO
2
HO
HO
HO
OH
OH
HO
O
OH
HO
H 2 , Pd/C
OH
O
O
O
HO
O
O
OMe
O
HO
MeOH
93%
HO
HO
2
SCHEME 12.8
Linear synthesis of an alternating b -(1 ! 4)- b -(1 ! 3)-mannan.
1. BSP, Tf 2 O, TTBP
CH 2 Cl 2 , -78°C
OBn
OBn
2.
O
Ph
O
O
Ph
O
O
OBn
O
HO
OBn
O
O
PMP
O
O
PMP
SPh
O
O
O
BnO
SPh
BnO
3. P(OEt) 3 62%
SPh
1. AcOH, CH 2 Cl 2 (89%)
2. n -Bu 2 SnO, PhMe
3. BnBr, CsF (86% over 2 steps)
4. Donor 2, BSP, Tf 2 O, TTBP
5. P(OEt) 3 (79%)
OBn
O
1. BSP, Tf 2 O, TTBP
CH 2 Cl 2 , -78°C
3. AcOH, CH 2 Cl 2 (89%)
4. n -Bu 2 SnO, PhMe
5. BnBr, CsF (86% over 2 steps)
Ph
O
O
BnO
2.
BnO
HO
OBn
SPh
O
Donor 2
OMe
BnO
BnO
O
OBn
OBn
OBn
O
Ph
O
O
Ph
O
O
O
BnO
O
O
OBn
OBn
BnO
HO
OMe
+
OBn
O
O
O
BnO
Ph
O
O
O
O
SPh
BnO
BnO
BnO
88%
BSP, Tf 2 O, TTBP, CH 2 Cl 2 , -78°C
BnO
O
OBn
OBn
O
Ph
O
O
OBn
BnO
O
O
OMe
OBn
O
Ph
O
O
BnO
BnO
O
O
O
OBn
OBn
O
O
Ph
O
BnO
O
O
BnO
BnO
(
α/β
= 1.5:1)
isomer
H 2 , Pd/C, MeOH
β
93%
HO
O
HO
OH
OH
HO
HO
HO
HO
HO
O
OH
HO
O
OH
OH
OH
O
O
HO
O
OMe
O
O
O
O
HO
O
HO
HO
HO
SCHEME 12.9
Block synthesis of an alternating b -(1 ! 4)- b -(1 ! 3)-mannan.
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