Method for preparing aromatic alkynes through cross-coupling of nitroaromatic hydrocarbons and aryl-terminated alkynes under catalysis of transition metal

Abstract

The invention discloses a method for preparing aromatic alkynes through cross-coupling of nitroaromatic hydrocarbons and aryl-terminated alkynes under the catalysis of transition metal. The method comprises a step of subjecting nitroaromatic hydrocarbons and aryl-terminated alkynes to a cross-coupling reaction in a solution system of a palladium-containing catalyst, a copper-containing catalyst, aphosphine ligand and an amine ligand in a protective atmosphere so as to obtain aromatic alkynes. According to the method, the cheap, easily available and polar nitroaromatic hydrocarbons are used asan electrophilic reagent for synthesis of the aromatic alkynes, so a series of advantages in traditional Sonogashira coupling can be compensated. The method of the invention has the following advantages: (1) usage of expensive halogenated hydrocarbons hard to prepare can be avoided; (2) in the process of multiple coupling reactions, the polarity of nitro groups allows coupling products to have polarity different from the polarity of raw materials and by-products, so the coupling products can be easily separated through column chromatography; and (3) the transition metal is employed for homogeneous catalysis, so cross-coupling is expected to be smoothly carried out under mild conditions, and the tolerance range of function groups is wide.

Description

technical field [0001] The present invention relates to a method for synthesizing aromatic alkynes, in particular to a method for synthesizing aromatic alkynes by cross-coupling terminal aryl alkynes with nitroaromatics as electrophile synthons under transition metal catalysis, It belongs to the field of organic synthesis. Background technique [0002] The two carbon atoms of the alkyne bond adopt sp hybridization to form two π bonds that are perpendicular to each other and the molecular axis, and the molecular structure is linear. made of. Alkynes are a class of compounds containing alkyne bonds. They have a unique linear rigid structure and conjugated system. They are widely used in the fields of medicine and optoelectronic materials. For example, the rigid linear lipophilic alkyne derivatives have certain biological activities and can be used Antibacterial and anticancer, etc.; π-conjugated aromatic alkynes have a rigid skeleton and abundant π electrons, which are often...

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Problems solved by technology

[0003] Transition metal palladium copper (Pd / Cu) catalyzed Sonogashira coupling reaction of terminal alkynes and halogenated arenes is one of the most effective methods for preparing aromatic alkynes, which has the advantages of high yield and mild reaction conditions, but has the following disadvantages: (1 ) Halogenated hydrocarbons often need to be prepared through multi-step reactions under harsh conditions, the price is more expensive and the halogens pollute the environment; (2) when there are multiple coupling sites, the coupling product and the halogenated hydrocarbon raw material and by-products Have similar polarity and be difficult to separate by column chromatography; Stable reagents and high pressure reaction conditions, the overall yield is low and the product is difficult to separate

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