[sharbeldam]

I tried, but I got stuck. I cant do a wolff kishner, And I think I also started wrong since the major product didnt really help me.
Any tips?
problem attached.
(the first step is lindlar)

[rolnor]

How about use Lindlar, then Pd(PPh4) to isomerize/move the double bond into the ring as a start?

[sharbeldam]

I appreciate that rolnor, but This reaction is not included in the syllabus and I am as a tutor still not familiar with it. Id be happy for a link that explains it.

Any other ways? in my idea, it does make the double bond to the left but the problem is that it wouldnt be the major product :/

[rolnor]

Here is a link:

https://pubs.rsc.org/en/content/articlelanding/2019/cc/c9cc00223e#!divAbstract

The double bond in this case should migrate into the ring I think. Then the next step would be ozonolysis.

[sharbeldam]

Ok this is what I did, Id get aldehyde and ketone in the chain tho. I want to turn the aldehyde into halide without touching the ketone . ill keep thinking of it

[rolnor]

OK, I see now that you have the ozone-step. To reduce aldehyde in presence of ketone should be possible, maybe NaBH3CN att the right pH?

[sharbeldam]

I thought it reduces imines but not ketones and aldehydes, so its more selective to aldehydes?

[rolnor]

If you have a little more acidic conditions it will reduce aldehydes selective but I am not sure about the pH. Also diisobutylaluminiumhydride at -78 could work.

[rolnor]

Here is a better option;

https://en.wikipedia.org/wiki/Sodium_triacetoxyborohydride

[hollytara]

Will BH3-THF reduce the ketone?  It will reduce an acid - so if you cleave 1-ethylcyclopentene with permanaganate instead of ozone to get the ketone and acid, you can then reduce the acid with BH3-THF and make the alcohol.  The mechanism of reduction is complex, but it works for acids but not esters or ketones or aldehydes.  (While you can't reduce a ketone by itself with BH3, I am not certain that if you have both a ketone and an acid that reduction will be selective - the triacetoxyborane that rolnor suggests is a lot like the intermediate in the acid reduction.)

But I think they teach it at the sophomore level as being selective for acids.