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Organic Synthesis help

Hello! I'm trying to prepare for the Chemistry Olympiad next week by doing some past papers, and the organic synthesis is blowing my mind... It's questions (6d) in the 2020 paper: https://edu.rsc.org/download?ac=515424 (I'll try and attach a photo of the question too). Some of the reagents like LiAlH4 I recognise from A-level, but others like Na2S or SO2Cl2 have me completely confused as to what they might do to a compound- whether they act as a nucleophile, electrophile or something else. I'm sure they're looking for us to apply our knowledge and figure it out, but I'm having a hard time knowing where to start. Would anyone have any advice on how to approach these synthesis questions and figure out what compounds are made even if you don't recognise the reagents? I'd be really grateful for any advice, whether it's specific to the question above or just generally :smile:
(edited 4 months ago)
Reply 1
Reply 2
I think your right in that it is pointless trying to remember what each reagent does, though you should get a basic grasp of reagents from your A-level course, if you have something like sodium sulfide, the sodium ion is not really ever going to do anything, it will most like;y simply be there as a spectator ion, the sulfide ion however can be used as a reducing agent, you could perhaps realise that because it has many oxidation states that the presence of sulfur or sulfide ions in low oxidation states are likely to be good reducing agents. SO2Cl2 is similar to thionyl chloride SOCl2 and these groups of compounds are used as chlorinating agents, they are generally mild agents and reactive cleanly. You can swap the Cl for other halogens. Good luck and don't get stressed, its meant to be fun!
Reply 3
Original post by Scanjo63
I think your right in that it is pointless trying to remember what each reagent does, though you should get a basic grasp of reagents from your A-level course, if you have something like sodium sulfide, the sodium ion is not really ever going to do anything, it will most like;y simply be there as a spectator ion, the sulfide ion however can be used as a reducing agent, you could perhaps realise that because it has many oxidation states that the presence of sulfur or sulfide ions in low oxidation states are likely to be good reducing agents. SO2Cl2 is similar to thionyl chloride SOCl2 and these groups of compounds are used as chlorinating agents, they are generally mild agents and reactive cleanly. You can swap the Cl for other halogens. Good luck and don't get stressed, its meant to be fun!

Thanks so much for your help, I really appreciate it! 😁

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