Органическая химия - Лекции - МГУ - Ненайденко - 2004 / Лекция 23 - Защитные группы
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Защитные группы, снимаемые восстановительным элиминированием с участием цинка
Cl |
Cl Cl |
Cl |
Cl ZnCl |
- Cl2C=CH2 |
O |
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Zn0 |
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AcO |
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O |
HOAc |
O |
- ZnCl(OAc) |
R OH |
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R |
O |
R |
O H |
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H |
H N |
OCH2CCl3 Zn, HOAc |
H |
OH |
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TCE |
100 % |
H N |
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Fmoc N |
O O |
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N |
O O |
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Fmoc |
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NHBoc |
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NHBoc |
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O OC6F5 |
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OMe |
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OMe |
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O |
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O |
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Cl |
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1. Zn, HOAc, r.t., 12 h |
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O |
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Cl |
O |
H |
O |
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O H |
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O |
Cl |
2. DMAP, Pyr, 95 °C, 14 h |
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N |
N |
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N |
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N |
Troc |
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H |
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H |
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HN |
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N |
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HN |
N |
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Ac |
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Ac |
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EtO |
OEt |
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EtO OEt |
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Zn |
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N-Troc |
EtOH ∆, 1 h |
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NH |
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99 % |
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OH |
O |
Cl3C-CH2OH |
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OH |
O |
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OH DCC, DMAP |
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OCH2CCl3 |
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NHBoc |
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NHBoc |
99 % |
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Troc |
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Troc |
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N |
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N |
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N |
TrocCl |
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Cl |
+ |
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CH2Cl2 |
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N |
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COOMe |
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N |
COOMe |
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N |
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COOMe |
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H |
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H |
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H |
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Защитные группы, снимаемые окислением
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O |
ROH |
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OROH |
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OR |
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H |
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H |
+ H2O |
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H |
MeO |
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MeO |
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- H+ |
MeO |
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OR |
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OR |
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OR |
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H |
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H |
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H |
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MeO |
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SET |
MeO |
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MeO |
+ |
+ |
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+ |
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O |
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O |
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O |
Cl |
CN |
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Cl |
CN |
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Cl |
CN |
Cl |
CN |
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Cl |
CN |
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Cl |
CN |
O |
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O |
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OH |
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OH |
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O |
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Cl |
CN |
+ H+ |
Cl |
CN |
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Cl |
CN |
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Cl |
CN |
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OH |
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OH |
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NHBn |
CAN (3.7 equiv.) |
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NHBn |
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COOMe |
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COOMe |
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Ph |
MeCN-H O, r.t., 1-3 h |
Ph |
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2 |
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OPMB |
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OH 95 % |
O |
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DDQ |
O |
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O |
O |
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OBn |
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OBn |
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O |
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O |
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O |
O |
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O |
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O |
HO |
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O |
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81% |
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Нуклеофильный разрыв C-O связи
R |
O |
Nu Li |
R |
O |
Li + MeNu |
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CH3 |
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O |
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O |
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COOMe |
NaCl |
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DMF / H2O, ∆ |
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O |
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- MeCl, -CO2 |
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O |
MeO |
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OMe |
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MeO |
OMe |
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OMe OMe |
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OMe OMe |
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67 % |
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LiI |
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O |
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collidine, ∆ |
O |
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MeOOC |
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- MeCl, -CO2 |
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95 %
Аллильные защитные группы
RO |
+ RhI |
RO |
RO |
H |
- RhI |
H RhI |
RhIII |
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H |
+ H3O+ |
RO |
+ RhI |
RO |
ROH |
- RhI |
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- EtCHO |
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RhI |
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AcO AcO
Me
O
OAc
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O |
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Pd[Ph3P]4 (10 mol %) |
O H |
t |
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NHAc |
O H |
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dimedone (8 eq) |
N |
COOBu |
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NHAc |
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AcO |
O |
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t |
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THF, r.t., 30 min |
O NH2 |
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AcO |
O AcO |
N |
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COOBu |
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NHAc |
HN |
O |
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92 % |
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OAc |
O |
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O
Aloc
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RhCl[Ph3P]3 (6.65 mmol) H N |
OBn |
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N |
N OBn |
2 |
N |
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MeCN - H2O (4:1) |
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COOBut Ac |
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COOBut |
Ac |
∆, 1.5 h |
84 % |
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Фотохимическое снятие защиты
O |
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O |
O |
N O |
hν |
N OH |
N OH |
OR |
OR |
OR |
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O |
O |
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N |
N |
ROH |
+ |
OH |
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O |
OR |