enter image description here I circled what I believe to be the chiral centers and I added the locants for the longest carbon chain. One of the chiral centers is in a side chain, so that carbon doesn't have a locant. How should its absolute configuration be included into the IUPAC name?

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    $\begingroup$ Side chain have their locants. Your question is rather how to number them and even more general, how to number/call a molecule and has little to do with chirality. $\endgroup$ – Alchimista Dec 5 '19 at 7:56
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    $\begingroup$ @AniruddhaDeb look, you can’t just change somebody else’s question like that to fit your answer. $\endgroup$ – orthocresol Dec 5 '19 at 17:16

The IUPAC name of the given compound without chirality would be $$\text{10-bromo-2-methyl-5-(butan-2-yl)-undec-3-yne}$$

If we want to say that it has an $\text{R}$ configuration at locant 5 and 10 and an $\text{S}$ configuration at the sec-butyl group, then the name becomes: $$\text{(5} \textit{R}\text{,10}\textit{R}\text{)10-bromo-2-methyl-5-((2}\textit{S}\text{)butan-2-yl)-undec-3-yne}$$


Butyl Group - Wikipedia

The preferred IUPAC name of sec-butyl is butan-2-yl

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    $\begingroup$ Your name isn’t correct. Firstly, the C10 substituent isn’t a methyl. Secondly, substituent prefixes should be given in alphabetical order (neglecting multiplicative di, tri,...). Thirdly, some of your spaces should be hyphens and some should not even be there. Lastly, the stereodescriptors R and S should be italicised. $\endgroup$ – orthocresol Dec 5 '19 at 10:51
  • $\begingroup$ So then if the hydrogens on the chiral centers are all dashed, it could be (5R,10R)-10-bromo-2-methyl-5-((S)-1-methylpropane)undec-3-yne $\endgroup$ – user193661 Dec 6 '19 at 22:59

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