Q on Destroyer O-Chem #7

[bruinguy083]

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Can anyone explain the curved arrow mechanism for this problem, or simply explain this problem in general? I understand the conditions for an aldol condensation, I just find it hard drawing the product. Any feedback would be greatly appreciated.

 

[RING12]

Can anyone explain the curved arrow mechanism for this problem, or simply explain this problem in general? I understand the conditions for an aldol condensation, I just find it hard drawing the product. Any feedback would be greatly appreciated.

first you should look for alpha hydrogen. and also keep in your mind as you said aldol which means we should get one carbonyl and one oH in the product. then always the aldehyde you have just take one of the alpha hydrongs off of it make if ch3-ch-c=o-h and then add the second aldohyde to the ch part of this aldehyde. but do not forget as i said we need oH what you should is start adding the second aldehyde from ch of first aldehyde just know to connect them from here always and the second carbonyl carbon will switch to oH always. and if you see HEAT then after this part in third step there is an elimination and we lose on h from the aldeyde and the oh from the alcohol part and we get a double bond. i hope that helped you.

 

[bruinguy083]

wow, and i was trying to deal w/ curved arrows. that really helped alot, thanks a bunch 🙂

 

[Donjuan]

first you should look for alpha hydrogen. and also keep in your mind as you said aldol which means we should get one carbonyl and one oH in the product. then always the aldehyde you have just take one of the alpha hydrongs off of it make if ch3-ch-c=o-h and then add the second aldohyde to the ch part of this aldehyde. but do not forget as i said we need oH what you should is start adding the second aldehyde from ch of first aldehyde just know to connect them from here always and the second carbonyl carbon will switch to oH always. and if you see HEAT then after this part in third step there is an elimination and we lose on h from the aldeyde and the oh from the alcohol part and we get a double bond. i hope that helped you.

There was an aldol problem in Topscore 1, I don't remember where exactly question, but I believe it was somewhere in the 70's, where you get the base, I don't recall heat being used, and of two answer choices, one was the aldol condensate and the other was the alpha, beta unsaturated aldehyde. I guess if we don't see the heat, and given a choice between these two products, it would be safe to pick the alpha, beta unsaturated product right?
Thanks for your help!

 

[hokie4life]

no i thought you get the alpha beta unsaturated aldehyde when there is a strong base and higher temperature, so if you don't have heat you shoudln't pick alhpa beata.... right?