[casualdehyde]

Hi guys, I am studying organometallic but encountered three reactions which I am not sure about. Could you please enlighten me as to how the following reactions proceed please?

I *think* i have figured out that reaction c is simply an addition where the triple bond cooridinates with metal and one of the PMe3 ligands are removed due to the bulkiness of that group ... am i right?

(Reactions attached as .png)

Thanks and best regards,

Haze.

[casualdehyde]

why no one wants to answer me ?   

[stewie griffin]

why no one wants to answer me ?   

Well I didn't answer because I don't remember too much from my organometallics course and didn't want to mislead you. However I will give my best shot.
A) You have a soft nucleophile (carbanion stabilized by two esters) and a soft electrophile (the π-allyl). The nucleophlie attacks the electrophile to give an η-1 alkyl group.
B) I'm not too sure. You've got a non-nucleophilic solvent/reagent present which I don't know what it does. However, the starting material reminds me of the Petasis reagent. So I think you will get elimination of CH₄ and formation of an ethylene ligand (see http://www.umich.edu/~chemh215/W06HTML/SSG5/ssg3/Petasis.htm)
C) I think you are right that a neutral PMe₃ is substituted for the alkyne.