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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: the_negro_puppy on June 30, 2006, 11:33:47 PM

Title: Mechanism for Reaction
Post by: the_negro_puppy on June 30, 2006, 11:33:47 PM

Hi, i am currently revising for my end of semester exam for Organic Chem 2.
Im really stumped on working out the mechanism for the following reaction:

(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fimg287.imageshack.us%2Fimg287%2F9177%2Fmech3sh.jpg&hash=bf1aeaa99059594ce58255d7533ca9ff74a1c1a8)

Any help would be greatly appreciated.

Title: Re: Mechanism for Reaction
Post by: swati on July 01, 2006, 04:51:00 PM

This is acid catalysed reaction of water with alkenes which results in formation of alcohol. This addition follows Markonikov rule according to which during the addition reactions of unsymmetrical alkenes more stable carbocation is formed .

Mechanism attached.

Title: Re: Mechanism for Reaction
Post by: Mitch on July 01, 2006, 07:42:30 PM

Oxygen in water will attack the tertiary sp2 carbon to start.

Title: Re: Mechanism for Reaction
Post by: swati on July 02, 2006, 03:06:59 PM

Quote from: Mitch on July 01, 2006, 07:42:30 PM

Oxygen in water will attack the tertiary sp2 carbon to start.

But the reaction will start by formation of the carbocation by acid .
Please correct me if I am wrong.

Title: Re: Mechanism for Reaction
Post by: Donaldson Tan on July 02, 2006, 10:24:41 PM

1. The H+ add across the C=C to form ⁺C-CH₃ (markonikov electrophillic addition)

2. The oxygen on the water molecule acts as a nucleophile and attacks the C⁺ site