浙江大学化学系有机合成化学OS1
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another stereoisomer is also produced,
the reaction is stereoselective.
Diastereoselective Diastereospecific
Enantioselective Enantiospecific
O
O
baker's yeast reaction
58,59 and 60,61 are called enantimers 58,60 and 59,61 are called diastereomers 62,63 are called meso compound
Example
64,65 are called enantiomers 66,67 are called enantiomers 63,67 and 63,66 are called diastereomers
Formation of Carbon-Carbon bonds via Radical and Carbenes
Introduction
1. The disconnection protocol 2. Stereochemistry 3. Lewis acid 4. Hard/soft acid/base theory
functional group iny
synthesis, of both large and small molecules, reveals that building up a carbon skeleton by carbon-carbon bond-
Stereospecific and Steroselective
If steroisomic starting materials react
to give a single stereoisomeric product,
it is a stereospecific reaction but if
Functional Group Exchange Reactions
Nucleophilic Species That Form Carbon-Carbon Bonds Electrophilic Carbon-Carbon Bond Forming Reactions Pericyclic Carbon-Carbon Bond Forming Reaction Protecting Groups
O O O O O O N N
HO2C O O O HO2C OH O O H O O O
NH2 O O O O Cl O Cl OH OH O
H
OH
O
O
O
t-BuOOt-Bu HBr
Br
LiN(iPr)2, THF O -780C O Li
O
1. Li Br 2. CuI OH O SOCl2 Cl O CuLi 2
2.1 Absolute configuration in chiral nonracemic molecules
When an atom is bound to four different groups in a tetrahedral arrangement, that atom is said to be stereogenic or chiral.
Regioisomers
If a reaction can produce two or more regioisomers it is regioselective or regiospecific. Regioselective: If a reaction gives a mixture products, we called the reaction regioselective. Regiospecific: If a reaction only gives one product, we called the reaction regiospecific.
ligand, the original assembly is prochiral. A ligand is a simply
group attached to the prochiral atom.
Example
Pro-S: A point ligand in a prochiral molecule whose replacement leads to an ( S ) center. Pro-R: A point ligand in a prochiral molecule whose replacement leads to an ( R ) center
1.新编有机合成化学, 黄宪,王彦广,陈振初，化学工 业出版社（65元） 2.有机合成，黄宪，高等教育出版社 3.现代有机合成化学, 吴毓林,姚祝军，科学出版社 （2001）. 4.手性合成——不对称合成及其应用，林国强，陈 耀全，陈新滋，李月明，科学出版社（2000）.
Contents
Introduction Oxidation Reduction Hydroboration
Example
Si face: The a→b →c priority according to the CIP rules is clockwise. Re face: The a→b →c priority according to the CIP rules is counterclockwise.
OH
O
3. Lewis acid
A Lewis acid is an electron pair acceptor
A Lewis base is an electron pair donor
A Brø nsted-Lowry acid is a proton donor
Example
Example
Example
2.2 Diastereomers
When there is more than one stereogenic center, the
maximum number of possible stereoisomers is predicted
by 2n rule. For n stereogenic centers there is a maxmum of 2n steroisomers.
There are molecules that do not possess a chiral center but generate a product with chiral center after a chemical reaction.
Definition of Prochiral
If a chiral assembly is obtained when a point ligand in a finite non-chiral assembly of point ligands is replaced by a new point
Cl Br
H Me b
a c
a b
(R)
d
c
d
Example
CIP Rules
4. When the first point of difference contains two or more identical atoms, proceed atom by atom down the highest priority chain to the next point of difference and apply rules 1, 2, or 3 to determine the priority. 5. If an atom is attached to another by a multiple bond (double or triple) both atoms are considerede to be duplicated. The duplicated atom is considered to have a valence of zero and has a lower priority than a real atom, if that is the only point of difference. 6. Lone electron pairs receive an atomic number of zero and are assigned the lowest priority.
forming reactions cannot be done successfully unless all
aspects of chemical reactivity, functional group interchange, conformations, and stereochemistry are well understood.
Erythro and threo, anti and syn
c a a c erythro b b a b c threo c b a
2.3 Chiral molecules without a stereogenic center
Example
Example
Example
(R)
2.4 Prochiral centers
1. The disconnection protocol
The total synthesis of complex natural products usually demands a thorough knowledge of reactions that form carbon-carbon bonds as well as those that change one
3
H > 2H > 1H
3. When the highest priority atoms are identical, compare the number of priority atoms at first point of different to distinguish them.
Examples
1. B2H6 2. NaOH H2O2 CrO3 O OH
2. Stereochemistry
• 2.1 Absolute configuration in chiral nonracemic molecules • 2.2 Diastereomers • 2.3 Chiral molecules without a stereogenic center • 2.4 Prochiral center • 2.5 Definition of selectivity
Example
2.5 Definition of selectivity
Chemoselective: Of two or more reactive functional groups, only one predominates. Chemospecific: Of two or more reactive functional groups, only one reacts.
有机合成 Organic Synthesis
主讲教师: 张玉红
主要目标:
巩固一些基本有机合成化学反应和概念. 学习一些新型有机合成化学反应.
学习一些基本的有机合成设计策略.
教材: Organic Synthesis Michael B. Smith Second Edition
主要参考书:
Cahn-Ingold-Prelog (CIP) rules
1. An atoms with a higher atomic number precede atoms of lower atomic number O > N > C >H 2. Isotopes with a higher mass number precede isotopes of lower mass number
the reaction is stereoselective.
Diastereoselective Diastereospecific
Enantioselective Enantiospecific
O
O
baker's yeast reaction
58,59 and 60,61 are called enantimers 58,60 and 59,61 are called diastereomers 62,63 are called meso compound
Example
64,65 are called enantiomers 66,67 are called enantiomers 63,67 and 63,66 are called diastereomers
Formation of Carbon-Carbon bonds via Radical and Carbenes
Introduction
1. The disconnection protocol 2. Stereochemistry 3. Lewis acid 4. Hard/soft acid/base theory
functional group iny
synthesis, of both large and small molecules, reveals that building up a carbon skeleton by carbon-carbon bond-
Stereospecific and Steroselective
If steroisomic starting materials react
to give a single stereoisomeric product,
it is a stereospecific reaction but if
Functional Group Exchange Reactions
Nucleophilic Species That Form Carbon-Carbon Bonds Electrophilic Carbon-Carbon Bond Forming Reactions Pericyclic Carbon-Carbon Bond Forming Reaction Protecting Groups
O O O O O O N N
HO2C O O O HO2C OH O O H O O O
NH2 O O O O Cl O Cl OH OH O
H
OH
O
O
O
t-BuOOt-Bu HBr
Br
LiN(iPr)2, THF O -780C O Li
O
1. Li Br 2. CuI OH O SOCl2 Cl O CuLi 2
2.1 Absolute configuration in chiral nonracemic molecules
When an atom is bound to four different groups in a tetrahedral arrangement, that atom is said to be stereogenic or chiral.
Regioisomers
If a reaction can produce two or more regioisomers it is regioselective or regiospecific. Regioselective: If a reaction gives a mixture products, we called the reaction regioselective. Regiospecific: If a reaction only gives one product, we called the reaction regiospecific.
ligand, the original assembly is prochiral. A ligand is a simply
group attached to the prochiral atom.
Example
Pro-S: A point ligand in a prochiral molecule whose replacement leads to an ( S ) center. Pro-R: A point ligand in a prochiral molecule whose replacement leads to an ( R ) center
1.新编有机合成化学, 黄宪,王彦广,陈振初，化学工 业出版社（65元） 2.有机合成，黄宪，高等教育出版社 3.现代有机合成化学, 吴毓林,姚祝军，科学出版社 （2001）. 4.手性合成——不对称合成及其应用，林国强，陈 耀全，陈新滋，李月明，科学出版社（2000）.
Contents
Introduction Oxidation Reduction Hydroboration
Example
Si face: The a→b →c priority according to the CIP rules is clockwise. Re face: The a→b →c priority according to the CIP rules is counterclockwise.
OH
O
3. Lewis acid
A Lewis acid is an electron pair acceptor
A Lewis base is an electron pair donor
A Brø nsted-Lowry acid is a proton donor
Example
Example
Example
2.2 Diastereomers
When there is more than one stereogenic center, the
maximum number of possible stereoisomers is predicted
by 2n rule. For n stereogenic centers there is a maxmum of 2n steroisomers.
There are molecules that do not possess a chiral center but generate a product with chiral center after a chemical reaction.
Definition of Prochiral
If a chiral assembly is obtained when a point ligand in a finite non-chiral assembly of point ligands is replaced by a new point
Cl Br
H Me b
a c
a b
(R)
d
c
d
Example
CIP Rules
4. When the first point of difference contains two or more identical atoms, proceed atom by atom down the highest priority chain to the next point of difference and apply rules 1, 2, or 3 to determine the priority. 5. If an atom is attached to another by a multiple bond (double or triple) both atoms are considerede to be duplicated. The duplicated atom is considered to have a valence of zero and has a lower priority than a real atom, if that is the only point of difference. 6. Lone electron pairs receive an atomic number of zero and are assigned the lowest priority.
forming reactions cannot be done successfully unless all
aspects of chemical reactivity, functional group interchange, conformations, and stereochemistry are well understood.
Erythro and threo, anti and syn
c a a c erythro b b a b c threo c b a
2.3 Chiral molecules without a stereogenic center
Example
Example
Example
(R)
2.4 Prochiral centers
1. The disconnection protocol
The total synthesis of complex natural products usually demands a thorough knowledge of reactions that form carbon-carbon bonds as well as those that change one
3
H > 2H > 1H
3. When the highest priority atoms are identical, compare the number of priority atoms at first point of different to distinguish them.
Examples
1. B2H6 2. NaOH H2O2 CrO3 O OH
2. Stereochemistry
• 2.1 Absolute configuration in chiral nonracemic molecules • 2.2 Diastereomers • 2.3 Chiral molecules without a stereogenic center • 2.4 Prochiral center • 2.5 Definition of selectivity
Example
2.5 Definition of selectivity
Chemoselective: Of two or more reactive functional groups, only one predominates. Chemospecific: Of two or more reactive functional groups, only one reacts.
有机合成 Organic Synthesis
主讲教师: 张玉红
主要目标:
巩固一些基本有机合成化学反应和概念. 学习一些新型有机合成化学反应.
学习一些基本的有机合成设计策略.
教材: Organic Synthesis Michael B. Smith Second Edition
主要参考书:
Cahn-Ingold-Prelog (CIP) rules
1. An atoms with a higher atomic number precede atoms of lower atomic number O > N > C >H 2. Isotopes with a higher mass number precede isotopes of lower mass number