Ochem question and some nomenclature

[kov82]

1) for turning trans-1,2-dibromocyclodecane into an alkyne , my book uses NaNH2 150 degrees for two different problems

I know when to use that and fused KOH /200 degrees for straight chains to get terminal or internal alkynes but for the example above could I use KOH/200 degrees just as easily for that reaction? if not why? (I'm only asking since my book never uses the KOH, I"m wondering if thats because you can't or the author just simply never did)

2) I wrote (E)-3-methyl-2-hepten-4-yne as (E)-5-methyl-5-hepten-3-yne , does the double bond get the smaller number because its closer to an end, has a substituent close to it, or because it gets "priority"? if methyl is moved closer to the triple bond but the triple bond and double bond stay where they are, which gets the smaller number in the name?

H-C::C-(CH2)4-C:::C-H I'm sure that the name is #-octen-#-yne, but which bond gets the smaller number in the name here? and why?

---

Members don't see this ad.

 

[kov82]

nobody?

 

[Sajitude]

1) for turning trans-1,2-dibromocyclodecane into an alkyne , my book uses NaNH2 150 degrees for two different problems

I know when to use that and fused KOH /200 degrees for straight chains to get terminal or internal alkynes but for the example above could I use KOH/200 degrees just as easily for that reaction? if not why? (I'm only asking since my book never uses the KOH, I"m wondering if thats because you can't or the author just simply never did)

2) I wrote (E)-3-methyl-2-hepten-4-yne as (E)-5-methyl-5-hepten-3-yne , does the double bond get the smaller number because its closer to an end, has a substituent close to it, or because it gets "priority"? if methyl is moved closer to the triple bond but the triple bond and double bond stay where they are, which gets the smaller number in the name?

H-C::C-(CH2)4-C:::C-H I'm sure that the name is #-octen-#-yne, but which bond gets the smaller number in the name here? and why?

Wish I could help but all I can do is push your thread to the top, been 2 years since I took the DATs. I love home important ochem is for the DATs and how worthless it is for dental school.

 

[Sublimation]

1) for turning trans-1,2-dibromocyclodecane into an alkyne , my book uses NaNH2 150 degrees for two different problems

I know when to use that and fused KOH /200 degrees for straight chains to get terminal or internal alkynes but for the example above could I use KOH/200 degrees just as easily for that reaction? if not why? (I'm only asking since my book never uses the KOH, I"m wondering if thats because you can't or the author just simply never did) for this one it does not matter. KOH and NaNH2 are the same thing...(very strong bases). with some added heat you will have an elimination reaction. givig you the alkyne.

2) I wrote (E)-3-methyl-2-hepten-4-yne as (E)-5-methyl-5-hepten-3-yne , does the double bond get the smaller number because its closer to an end, has a substituent close to it, or because it gets "priority"? if methyl is moved closer to the triple bond but the triple bond and double bond stay where they are, which gets the smaller number in the name? alkenes get higher priority then alkynes. and remember you want the smallest combination of numbers as possible...i hope it makes sense.

H-C::C-(CH2)4-C:::C-H I'm sure that the name is #-octen-#-yne, but which bond gets the smaller number in the name here? and why?

answers are in BOLD