Organic Chemistry Problem

[Mike Diamond]

Can someone figure out this question, i got it wrong on my exam and want to make sure how to do it before the finals.

Thanks

The question is asking for the full IUPAC name, including the R and S designature for the following compound

[BabcockHall]

Let's start with what you think that the answer is.

[Mike Diamond]

thats my attempt at top.

This is a clear picture of the question. 

i attempted, and my answer is (2R, 3S, 4S, 5R ,6S, 7R, 8S,) Octabrumo 1- decamethyl 

 

[hypervalent_iodine]

There are several things wrong with your answer. The first and most obvious being that you've said octabromo, but then only given stereochemistry for 7 of them. The second issue is that your syntax is not correct (missing hyphens, missing numbers, incorrect spelling). Thirdly, you have given incorrect stereochemical assignments for carbons 5, 7, and 8 (assuming you've numbered correctly). Lastly, you've said decamethyl, which indicates 11 carbons. There are only 10, and the methyl isn't a substituent; it's part of the parent chain. You've also not mentioned the parent functionality in the name at all (the alcohol). 

[Mike Diamond]

Is there anyway you can redraw this and give me the correct answer please. 

I have a final exam tomorrow at 9 am. Please help. 

Edited October 27, 2017 by Mike Diamond

[hypervalent_iodine]

I am sorry, but I am not inclined to just give you the answer. You don't need to redraw the molecule, what you have is fine. Here is what I would do:

1. Draw the structure.

2. Assign stereochemistry to your carbons and write then next to the appropriate carbon.

3. Identify the length of the parent chain and the parent functional group. This will form the suffix of the name. For example, if my parent functional group was an aldehyde and I have five carbons with no double or triple bonds on the parent chain, the end of the name would read pentanal. 'Pent' for five carbons, 'an' because it's all single bonds, and 'al' for the aldehyde. 

4. Number the carbons on the chain.

5. Identify the substituents, how many you have of each type, and which number carbon they are attached too. This will form part of the beginning of the compound name. So if you had 2 methyl groups on C-3 and C-5 and 3 chloro groups on C-3, C-4 and C-5, you'd have 3,4,5-trichloro-3,5-dimethyl. 

6. Place the stereochemical assignments plus the relevant numbers at the start in brackets.

Remember: place commas between two numbers and hyphens between a letter and a number. Syntax is important!

Try and rename your molecule now and I'll tell you if it's correct.