synthetictragicflaws.pdf
TRANSCRIPT
1
Sometimes the hardest part of doing a problem is being able to search out and find errors. Sometimes its because your eyes and brain keep repeating the mistakes over and over again and sometimes its because you are unaware of an actual error.
• For each of the following synthesis, identify the error(s) in the sequences shown that prevent them from being successful. Find the TRAGIC FLAWS!
• Rework the synthesis so you have the right order/reagents. Sequence 1:
Find the flaw(s):
Sequence 2:
Find the flaw(s):
Sequence 3:
Find the flaw(s):
H
O
OH OCH3
H
O
OHCH3OH, H+
H
O
OCH3
Zn(Hg) H3O+
OCH3
O
H2O, H2SO4
OH O
PCC
H
O O OH O
CH3OH, H+
H
O O
H
O H3CO OCH3 CH3MgBr
OH H3CO OCH3 H3O+ OH O
2
Sequence 4:
Find the flaw(s):
Sequence 5:
Find the flaw(s):
Sequence 6:
Find the flaw(s):
H
OH
O OH
H
OH
O CH3OH, H+
H
OH
H3CO OCH3NH2NH2
KOHH
H3CO OCH3
H3O+
H
O MgBr OH
HOH
O
H
O
HOH
OCH3OH, H+
HOH
H3CO OCH3 Ph3P=CH(CH3)
H
H3CO OCH3
H3O+H
O
OOH OH
3
Sequence 7:
Find the flaw(s):
Sequence 8:
Find the flaw(s):
OOHTMS-Cl NEt3
OTMSOH PCCOTMSO
CH3MgBr OTMSOH F- OOHNH2NH2
H2SO4
OH
HOH
O
OH
HOH
O
HPh3P=CH(CH3)
O H3O+
OO
O
H+ O
OHO
H
O
O
O
4
Sequence 9:
Find the flaw(s):
Sequence 10:
Find the flaw(s):
H
O
O
CH3OH
H+
H
O
H3CO OCH3 MgBr
OH
H3CO OCH3PCC
OH
H3CO OCH3Zn(Hg), H3O+
H3CO OCH3 H3O+ O
OH
OH
O OHO
OH
OH
OH
O
OHO
OH
HOOH
H+
OH
OHOO
1 equiv TMS-ClNEt3
OTMS
OHOO PCC OTMS
HOO
O
CH3MgBr
OTMSOO
OH
F-
H
O
OH O
5
Sequence 11:
Find the flaw(s):
Sequence 12:
Find the flaw(s):
H
O
OH
O
DHP, H+
H
O
OTHP
Ph3P=CH(CH2CH2CH3)
OTHPH3O+
OH
PCC
H
O
OH O
H
O
OH
O
TMS-ClNEt3
H
O
OTMS
Ph3P=C(CH3)(CH2CH3)
OTMSH3O
+
OH
PCC
H
O
OH O
6
Sequence 13:
Find the flaw(s):
Sequence 14:
Find the flaw(s):
H
O
OH
O
TMS-ClNEt3
H
O
OTMS
OTMS
H3O+
OHPCC
CH3MgBrOH
OTMS
O
OTMS
MgBrOH
OTMS
POCl3, pyridine
H
O
OH
O
OH
H
O
OH
TMS-ClNEt3 H
O
OTMS
O
OTMS
CH3CH2Br
H3O+
O
OH
OH N
7
Sequence 15:
Find the flaw(s):
Sequence 16:
Find the flaw(s):
OHNH2CH3
N Et2AlCNN
OH N
OH
NH2CH3
OH PCC O(CH3CH2)2CuLi
H+
N
OH N
OH
NH2CH3
OPCC
O(CH2CH3)2CuLi
H+
N