# Synthesis of 1-hexene from 1-octyne

This is my synthetic pathway. For one, is it plausible? For another, is it efficient?

1) Reduction of 1-octyne with hydrogen gas and Lindlar's catalyst to 1-octene.

2) Oxymercuration to install a hydroxyl group at the most substituted carbon. This creates 2-octanol.

3) Reaction with tosyl chloride and pyridine to create a sulfonate ester - a much better leaving group than an alcohol.

4) E2 elimination with sodium hydroxide and strong heating to create the internal, Zaitsev alkene.

5) Ozonolysis to create two aldehydes.

6) Reduction of longer aldehyde with hydrogen gas over transition metal to primary alcohol.

7) Dehydration of primary alcohol to alkene using a Lewis acid (aluminium trichloride in this case).

I guess this is just a paper exercise, since trying to make 1-hexene from octyne means you forget efficiency. A very useful and interesting exercise though. I agree with Ron about potential issues with step 4. I think sulfuric acid is worth trying for step 7 though and if it fails you can try stronger dehydrating agents that are less/non acidic or an indirect method like your tosylate elimination or even selenium chemistry. For step 6 I would use the standard $\ce{NaBH4}$ or $\ce{LiAlH4}$ for reduction.