[Elphabalives]

We've been given this reaction, and told to fill in the missing reagents. I've worked through a possible mechanism to help myself understand, but i need to know if i'm doing anything blatantly wrong. First, the given....
>

So getting from the cyano to a NH2C=O is easy.
Protonate the N
water comes in, and is then deprotonated
>
Nitrogen is then protonated again

Water then comes in and attacks the carbon, pushing the pi electrons to N, and that water is deprotonated
>

Now we have a geminal diol, which can go to a carbonyl with the loss of H2O

This is where i get stuck. I'm not sure how to get from this molecule to the product. Perhaps protonating the Oxygen, making the C have a positive charge, then having LiCH2CH3 (metal plus, whatever it's attached to minus) add the CH2CH3



Then maybe the unshared electrons on Nitrogen re-form the double bond to carbon, making the OH leave? Gives me this...

Which could then become the product.
 Is this plausible? Did i violate some horrible rule i didn't think of? The reagents being H30+ and LiCH2CH3?

[Jorriss]

I don't have time to carefully go over it atm, but just a quick note, a bronsted lowry acid likely won't work in this scenario. If you add a proton to your carbonyl, then add an organometallic reagent, it'll like just grab that proton instead of undergoing nucleophilic attack.

I'm no expert (I've never taken Organic so take what I say lightly), but I think organolithium reagents are as basic as they are nucleophilic.

Perhaps a lewis acid?


You seem to have done a lot of steps. Could just convert the nitrile to a carboxylic acid, then to a acyl chloride and lastly add a grignard?

[discodermolide]

We've been given this reaction, and told to fill in the missing reagents. I've worked through a possible mechanism to help myself understand, but i need to know if i'm doing anything blatantly wrong. First, the given....
>

So getting from the cyano to a NH2C=O is easy.
Protonate the N
water comes in, and is then deprotonated
>
Nitrogen is then protonated again

Water then comes in and attacks the carbon, pushing the pi electrons to N, and that water is deprotonated
>

Now we have a geminal diol, which can go to a carbonyl with the loss of H2O

This is where i get stuck. I'm not sure how to get from this molecule to the product. Perhaps protonating the Oxygen, making the C have a positive charge, then having LiCH2CH3 (metal plus, whatever it's attached to minus) add the CH2CH3



Then maybe the unshared electrons on Nitrogen re-form the double bond to carbon, making the OH leave? Gives me this...

Which could then become the product.
 Is this plausible? Did i violate some horrible rule i didn't think of? The reagents being H30+ and LiCH2CH3?

Hydrolyse the nitrile to the carboxylic acid, make the Weinreb amide and treat with ethyl Grignard

[cundi]

Please see Grignard reaction.

Addition of EtMgX, then hydrolisis affords targeted compound!