sir, you can prepare this unsaturated chloride from saturated acid ,which transform into acid chloride on reaction with sulfonyl chloride then treat with LDA,THF,-78degree temp and then use PhSeBr after this use peracid or peroxide or NaIO4.

Thanks to both of you. I don't know if I'm getting off-topic asking this, but seeing that it may be a little troublesome to handle the cinnamoly chloride, think it would be easier then to make the ester instead? What I try to do is I'm thinking of reacting the ester or the chloride halide moiety with the corresponding organolithium, like a 4-lithium phenol. Think it would be that straightforward or it would involve some kind of coupling?

http://upload.wikimedia.org/wikipedia/commons/4/41/Licochalcone_a.svg

You can start with the corresponding benzaldehyde deri. (If available commercially) and condensation with malonic acid in pyridine (Knoevenagel Condensation) would deliver the cinnamic acid compound which you can derivatise as and when desired.

 α,β-unsaturated acid chlorides can be prepared by treating the corresponding acid  with thionyl chloride or oxalyl chloride.