[arario]

You start with cyclopentanone.

You somehow want to achieve this sharpless epoxidation product...

Wouldn't this require cyclobutene as an intermediate, then O3/DMS to break the ring, then Wittig reactions with Ph3P= , then finally sharpless epoxidation?

Theoretically this would work, but cyclopentanone to cyclobutene???  How do I get there or maybe I can't?  Perhaps favorskii reaction?

Can someone provide step by step reagents and explanations? 

I'd appreciate that.  Thanks!

[kiwi]

for starters, count the number of carbons in the product. you have C6, which means you need to add a C1 synthon somewhere. For me, that screams out for the Corey-Chaykovsky reaction:

http://en.wikipedia.org/wiki/Corey-Chaykovsky_reagent .

Just where and how to deploy it i'll leave to you for now

[Fry]

Heh I dont know how feasible this is in the lab.. but on paper it looks good!

Bayer-villiger reaction on cyclopentanone to obtain lactone.

Cleavage of lactone to produce the 5-hydroxy-pentanoic acid

Oxidize to make an aldehyde out of the alcohol.

Aldol reaction to produce the 1-butenoic acid.

make a ketone outta the double bond and remove the carboxylic acid by de-carboxylating it.

From there it should be pretty straight forward, I dont think the last few steps of my synthesis would work at all in the lab... just paper dreams

[arario]

thx all!  Your chemistry powers impress me.