What are the conditions that affect the synthesis of diene

The electron effect of the group is the main factor, the dienes have repulsion group, the dienes have absorption group is conducive to the reaction, and can determine the product configuration

Reaction conditions light or heat influence the reaction process, which may lead to the specificity of the product configuration

(1) Dienes react in a cis-conformation under conditions of light or heat

(2) Dienes (conjugated dienes) can be joined, but also annular, such as cyclopentadiene, cyclohexadiene, etc

(3) When the double bond carbon atom of a dienophile is attached with an electron-absorbing group, the reaction is easy to proceed. Common dienophiles include:

CH2= CH-cho CH2= CH-COOh CH2= CH-Coch3 CH2=CH-NO2 CH2=CH-CN CH2= CH-cooch3 CH2= CH-CH2CL

(4) D - A reaction of high yield, wide scope of application is one of the important methods of organic synthesis, has an important place in theory and dienes synthesis reaction is neither ionic reaction, nor free radical reaction, but don't generate reactive intermediates and another step to complete the synergistic reaction when dienes body 2, A push electronic base, close and electronic dienes body, the product is given priority to with two substituent at 1, 4;

When the dienes have pusher electron groups at the no. 1 position and pull electron groups on the dienes, the products are mainly pseudo-o-para reaction with two substituents in the ortho position

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