Intermolecular ene reaction

This a little overdue…Some interesting chemistry reported in Journal of the American Chemical Society….Interesting not for the products that it produces but for the proposed mechanism, an intermolecular ene-reaction. From a retrosynthetic point of view one can imagine that the product of thisreaction could also be formed just as easily from the corresponding aldehyde via and Aldol reaction instead. However, the authors provide evidence to show that the reactants, as their enols, go through an ene-type process.

Given that this reaction occurs at room temperature simply by mixing the two substrates together is also noteworthy and makes me wonder why nobody had reported this before.



2 Responses to “Intermolecular ene reaction”

  1. milkshake Says:

    It is not realy ene reaction in classical sense – it is more akin to acid-catalyzed aldol. The keto ester is pretty acidic, it protonates the vinyl ether to make O-alkyl oxonium of the aldehyde which then easily condenses with the enolate. I don’t think it is a synchronnous transition state (like for example with ethyl glyoxylate and beta pinene) – even though you can draw it that way.

  2. walkerma Says:

    Sort of a “flipped” aldol since the acidic enol-H “protonates” the alpha-carbon of the aldehyde instead of the oxygen, like in the normal aldol.

    HC=CH-O-H—O=CHR normal aldol
    HC=CH-O-H—C(R)=CHOR’ “ene/aldol”

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: