1. Dear Drugs-Forum readers: We are a small non-profit that runs one of the most read drug information & addiction help websites in the world. We serve over 4 million readers per month, and have costs like all popular websites: servers, hosting, licenses and software. To protect our independence we do not run ads. We take no government funds. We run on donations which average $25. If everyone reading this would donate $5 then this fund raiser would be done in an hour. If Drugs-Forum is useful to you, take one minute to keep it online another year by donating whatever you can today. Donations are currently not sufficient to pay our bills and keep the site up. Your help is most welcome. Thank you.
    PLEASE HELP

Evidence that the availability of an allylic hydrogen governs the regioselectivity of the Wacker oxi

Evidence that the availability of an allylic hydrogen governs the regioselectivity of the Wacker oxi

  1. Electrolingus
    Evidence that the availability of an allylic hydrogen governs the regioselectivity of the Wacker oxidation.

    The allylic hydrogen is found to have a dramatic effect on the regioselectivity of the Wacker oxidation, leading to the postulation that an agostic hydrogen or enyl (s + p) complex helps to stabilise the key intermediate.

    The Wacker oxidation is a versatile reaction that has found broad application in synthetic chemistry for the functionalisation of alkenes.

    The s-bonded (b-hydroxyalkyl) palladium complex has been determined as the key intermediate in this reaction. However, the factors controlling the regiochemistry of the hydroxypalladation step to form this intermediate remain obscure. Although terminal alkenes nearly always give methyl ketones, suggesting that hydroxypalladation takes place according to Markovnikov’s principles, disubstituted alkenes give products that do not always obey these rules.A striking example of this paradox is the dramatically different regioselectivity observed with styrene (Markovnikov) and that of bmethylstyrene (apparent anti-Markovnikov). In this study we have identified that there are two key factors that control the regioselectivity: electronic effects (Markovnikov) and the availability of a hydrogen atom allylic to the double bond.

    Discussion Thread