Hey guys! Stuck on another one. See the image below. This one can also occur in only five steps.
My thoughts:
I turned the aldehyde into a secondary alcohol by adding a grignard reagent (I'm not quite sure which grignard I should be adding here), then I oxidize turning the secondary alcohol into a ketone. This is where I get stuck because I want the double bonded oxygen to move over a carbon, how do I do that? And how can I add the alkyne again in regards to this problem?
Any help or input would be appreciated! Thank you so much!!