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Method for preparing chiral carbon anion composite initiator

An initiator and anion technology, which is applied in the field of preparation of chiral carbanion combined initiators, can solve the problems that optically active polymers cannot be obtained, the types are few, and the polymerization is greatly affected by the solvent, etc. small effect

Inactive Publication Date: 2014-09-10
XIANGTAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

For achiral monomers, the polymerization usually adopts the initiation method of achiral initiator plus chiral ligand or the direct use of chiral anionic initiator, but the initiation method of achiral initiator plus chiral ligand The disadvantage is that the polymerization is greatly affected by the solvent. When the solvent and the chiral ligand compete for the initiation center, it is possible not to obtain an optically active polymer (Asymmetric Polymerization.Chem.Rev.1994,94:349-372 .), and the use of chiral anionic initiators to directly initiate polymerization can avoid this problem
Yet the kind of chiral anion initiator reported in literature is few at present and mainly concentrates on oxyanion initiator and nitrogen anion initiator (Synthetic Helical Polymers:Conformation and Function, Chem.Rev.2001,101:4013-4038), almost There is no report of monomer polymerization initiated by chiral carbanion initiator

Method used

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  • Method for preparing chiral carbon anion composite initiator
  • Method for preparing chiral carbon anion composite initiator
  • Method for preparing chiral carbon anion composite initiator

Examples

Experimental program
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Effect test

Embodiment 1

[0045] A preparation method of a chiral carbanion combination initiator, comprising the steps of:

[0046] Dissolve 10 mmol of (S)-type (4-isopropyloxazole) 1-substituted fluorene in toluene, add an equivalent amount of n-butyllithium pentane solution, and stir at room temperature to obtain a combined initiator solution.

[0047] Drop this initiator solution into a toluene solution containing 20 times the equivalent of ethyl methacrylate at -78°C under the protection of nitrogen, stir for 2 hours, drop into methanol to terminate the polymerization, and then drop the mixed solution into a large amount of methanol to obtain a polymer , the measured specific rotation at 365nm is +2.8°.

Embodiment 2

[0049] A preparation method of a chiral carbanion combination initiator, comprising the steps of:

[0050] Dissolve 10 mmol of (S) type (4-tert-butyloxazole) 2-substituted fluorene in toluene, add an equivalent amount of n-butyllithium pentane solution, and stir at room temperature to obtain a combined initiator solution.

[0051] Drop this initiator solution into a toluene solution containing 50 times the equivalent of butyl isocyanate at -78°C under the protection of nitrogen, stir for 2 hours, drop into methanol to terminate the polymerization, and then drop the mixed solution into a large amount of methanol to obtain a polymer , the measured specific rotation at 436nm is -15.2°.

Embodiment 3

[0053] A preparation method of a chiral carbanion combination initiator, comprising the steps of:

[0054] Dissolve 10 mmol of (R) type (4-benzyloxazole) 1-substituted fluorene in tetrahydrofuran, add an equivalent amount of sec-butyllithium hexane solution, and stir at room temperature to obtain a combined initiator solution.

[0055] Drop the initiator solution into the tetrahydrofuran solution containing 50 times the equivalent of diphenylmethyl acrylate under the protection of nitrogen at -78°C, stir for 2 hours, drop methanol to terminate the polymerization, and then drop the mixed solution into a large amount of methanol to obtain polymerization The measured specific rotation at 365nm is +17.3°.

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Abstract

The invention discloses a method for preparing a chiral carbon anion composite initiator. The method comprises the following processes: (1) by taking chiral oxazole-substituted fluorine as a reagent, dissolving into tetrahydrofuran or methylbenzene; (2) adding pentane or hexane solution of lithium alkylide to the solution obtained in the step (1), and agitating at room temperature, so as to obtain a composite initiator solution; and (3) adding one or more monomer solutions to the composite initiator solution obtained in the step (2) to initiate anionic polymerization. By adopting the composite initiator applied to the method disclosed by the invention, chiral carbon can be introduced to the initial end of the polymer, so as to prepare the chiral polymer.

Description

technical field [0001] The invention relates to a preparation method of a chiral carbanion combined initiator. Background technique [0002] The synthesis of optically active chiral polymers is currently a very active research field, because optically active chiral polymers show some unique properties, such as molecular chiral recognition ability, asymmetric catalytic ability, etc., and are used in biomedicine Fields show potential application prospects, etc. Optically active chiral polymers can be divided into two categories according to their sources, one is natural optically active polymers, and the other is synthetic optically active polymer compounds. The sources of natural optically active polymers are limited, and the diversity of structures is far from meeting people's needs for asymmetric catalysis and chiral recognition. Therefore, people focus on artificially synthesizing optically active polymers. [0003] Artificially synthesized optically active chiral polyme...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F4/48C08F4/00C08F120/18C08F112/08C08F120/54C08F112/32C08F112/12C08G18/02C08G73/00
Inventor 曹靖黄一玲胡伟
Owner XIANGTAN UNIV
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