按Lehn的定义, 超分子化学就是"分子组装和分子间键的化学 chemistry beyond the molecule".它是研究超分子或分子超结构的形成,性质及应用的化学,包括 分子识别原理,受体化学,分子自组装,超分子光化学,超分子电化学,超分子催化化学,超分子工程学,超分子生命科学等.
一句话,研究涉及分子减弱作用的朋友欢迎来看看
『一周一水』2008.3.19-3.27【C——N键的构建】
上一篇 / 下一篇 2008-03-19 22:15:30 / 个人分类:实验相关
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zjinan发布于2008-03-19 22:06:26
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给出的都是精华!!!!!!!!!!!!谢谢!!
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cc136520 发布于2008-03-19 22:08:42
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Gabriel Synthesis
Potassium phthalimide is a -NH2-synthon which allows the preparation of primary amines by reaction with alkyl halides. After alkylation, the phthalimid is not nucleophile and does not react anymore. Product is cleaved by reaction with base or hydrazine, which leads to a stable cyclic product.
Mechanism
Note: Phthalimide is acidic!
Cleavage:
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Recent Literature
Organic Reactions in Ionic liquids: N-Alkylation of Phthalimide and Several Nitrogen Heterocycles
Z.-G. Le, Z.-C. Chen, Y. Hu, Q.-G. Zheng, Synthesis, 2004, 208-212.
A convenient Two-Step Procedure for the Synthesis of Substituted Allylic Amines from Allylic Alcohols
S. E. Sen, S. L. Roach, Synthesis, 1995, 756-758
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cc136520 发布于2008-03-19 22:10:00
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Curtius Rearrangement

The Curtius Rearrangement is the thermal decomposition of carboxylic azides to produce an isocyanate. These intermediates may be isolated, or their corresponding reaction or hydrolysis products may be obtained.
The reaction sequence - including subsequent reaction with water which leads to amines - is named the Curtius Reaction. This reaction is similar to the Schmidt Reaction with acids, differing in that the acyl azide in the present case is prepared from the acyl halide and an azide salt.

Mechanism
Preparation of azides:

Decomposition:

Reaction with water to the unstable carbamic acid derivative which will undergo spontaneous decarboxylation:


Isocyanates are versatile starting materials:

Isocyanates are also of high interest as monomers for polymerization work and in the derivatisation of biomacromolecules.
Recent Literature

Boc-Protected Amines via a Mild and Efficient One-Pot Curtius Rearrangement
H. Lebel, O. Leogane, Org. Lett., 2005, 7, 4107-4110.

Radical Azidonation of Aldehydes
L. Marinescu, J. Thinggaard, I. B. Thomsen, M. Bols, J. Org. Chem., 2003, 68, 9453-9455.

Radical Azidonation of Aldehydes
L. Marinescu, J. Thinggaard, I. B. Thomsen, M. Bols, J. Org. Chem., 2003, 68, 9453-9455.
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cc136520 发布于2008-03-19 22:10:43
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Delépine Reaction
The Delépine Reaction allows the synthesis of primary amines from alkyl halides by the reaction with hexamethylentetramine (urotropine) and subsequent acidic hydrolysis of the resulting quartenary ammonium salt.
Mechanism
An SN2 reaction leads to the hexamethylentetramine salt. In chloroform, the starting materials are soluble wheareas the products crystallize out. It is usually not possible to purify the salt:
Hexamethylenetetramine is formed in nearly quantitative yield from the condensation of ammonia and formaldehyde.
The compound is rather stable, although dihetero-substituted methylene groups are usually highly reactive. In neutral, aqueous solution, urotropine remains stable even at elevated temperatures. Urotropine decomposes in dilute aqueous acid, and the derived ammonium salts also decompose to form the amine hydrochloride and formaldehyde (and formaldehyde diethylacetal):
During acidic hydrolysis or ethanolysis, semiaminals are formed first; these further decompose to yield formaldehyde or the diethylacetal, ammonium salt and the amine hydrochloride:
For a review of the uses of hexamethylenetetramine, a versatile reagent in organic synthesis, please refer to Blažević (Synthesis, 1979, 161-176. DOI).
Recent Literature

A Convenient Route to 3-Pyrroline Utilizing the Delépine Reaction
S. Brandänge, B. Rodriquez, Synthesis, 1988, 347-348.

Reactions of alkyl (halomethyl)furancarboxylates with hexamethylenetetramine
I. M. Lapina, L. M. Pevzner, A. A. Potekhin, Russ. J. Gen. Chem., 2006, 1304-1309.
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cc136520 发布于2008-03-19 22:11:30
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Mitsunobu Reaction


The Mitsunobu Reaction allows the conversion of primary and secondary alcohols to esters, phenyl ethers, thioethers and various other compounds. The nucleophile employed should be acidic, since one of the reagents (DEAD, diethylazodicarboxylate) must be protonated during the course of the reaction to prevent from side reactions.
Suitable nitrogen nucleophiles include phthalimide or hydrogen azide; subsequent hydrolysis (in the case of using phthalimide, see Gabriel Synthesis) or selective reduction (in the case of azide formation, see Staudinger Reaction) makes the corresponding amines accessible.
Mechanism
The triphenylphosphine combines with DEAD to generate a phosphonium intermediate that binds to the alcohol oxygen, activating it as a leaving group. Substitution by the carboxylate, mercaptyl, or other nucleophile completes the process.


The reaction proceeds with clean inversion, which makes the Mitsunobu Reaction with secondary alcohols a powerful method for the inversion of stereogenic centers in natural product synthesis.

Side Reaction:









