Master Organic Chemistry Reaction Guide

Formation of cyclopropanes from alkenes using methylene carbene (:CH2)

Description: Alkenes treated with methylene carbene (:CH2) will form cyclopropanes.

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Real-World Example:

Org. Synth. 1953, 33, 15
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Comment section

6 thoughts on “Formation of cyclopropanes from alkenes using methylene carbene (:CH2)

  1. Why do carbenes not react with alkynes? Has it got to do with the angle strain in the product which makes it unstable?

    Also, how do ZnCu react with CH2I2? Is ZnCu a catalyst? Where can I find the mechanism?

    1. Carbenes can react with alkynes to give cyclopropenes, but it’s a slower reaction due to the fact that the products (cyclopropenes) have more ring strain. Generally cyclopropanation of alkynes is not covered in these introductory courses, so it isn’t mentioned here.

  2. wow it was a very nice information!!!!
    i just gone through all the reactions of alkenes it is very helpfull for me!!!
    thank you for uploading them in website!!!!

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