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Chemistry Homework Help => Organic Chemistry => Topic started by: amimi on January 13, 2026, 01:31:58 AM

Title: Synthesis Question-acetone to propyne
Post by: amimi on January 13, 2026, 01:31:58 AM
Hello, I would appreciate some help with this question, thank you!
Screenshot 2026-01-12 at 10.29.07 PM.png
Title: Re: Synthesis Question-acetone to propyne
Post by: uma on January 14, 2026, 07:18:33 AM
acetone to propyne synthesis.jpg
 
Step 1 (reduce ketone to alcohol):

NaBH₄, MeOH (or LiAlH₄, then workup)
Gives 2-propanol
Step 2 (dehydrate alcohol to alkene):

conc. H₂SO₄, heat (or POCl₃/pyridine for a cleaner dehydration)
Gives propene

Step 3 (make alkyne from alkene):
1) Br₂ (CCl₄ or CH₂Cl₂) → vicinal dibromide
2) excess NaNH₂, liquid NH₃ (typically 2–3 equiv) → double elimination
3) H₂O / NH₄Cl workup