[kevin_lofgren]

I'm having a problem determining how a product is formed. The reaction is between 1-iodocycloethene and trimethylsilyl ethene (ethene with TMS bonded to one of the carbons). The conditions are

Pd(OAc)2 (3 mol %)
Et3N
DMSO
100 C
15 h

The product I would expect is only 15% (not positive how to name) 1-(2-trimethylsilylethene)cyclohexene.  57% is the product I can't figure out!  It is 1-vinylcyclohexene.  The other percentage is just   1-iodocyclohexene.
I haven't worked too much with TMS. I'm wondering if it is some palladium independent reaction I don't know about. When silver ions are added, the temperature is dropped to 50 C and the reaction is run for 3h the major product is the one I expected above. This isn't a surprise to me but if I can please get some help with the first reactions major product that would be great. Thank you.

[kevin_lofgren]

Here is one possible explanation. I'm really going off on my own here and having trouble finding detailed introductions to palladium catalyzed reactions so it could be way off. Once the H-Pd-I is released after forming the 15% product it reacts with the same molecule but in a wa that puts the palladium metal on the carbon closest to the cyclohexene. Then the palladium leaves and forms a pi bond kicking off the TMS group

[Babcock_Hall]

I'm having a problem determining how a product is formed. The reaction is between 1-iodocycloethene and trimethylsilyl ethene (ethene with TMS bonded to one of the carbons).

Do you mean 1-iodocyclohexene?

[clarkstill]

I think vinyl silanes are quite prone to protodesilyation (see e.g. Tet Lett 1995, 9505), although I'm not sure whether in this case the palladium is involved or not. It wouldn't be unreasonable for the NEt3H+ formed in situ to be acidic enough to protonate the C-Si bond, maybe assisted by nucleophilic attack of I- at silicon. I'm not sure how likely your hydropalladation-elimination proposal is - I think once H-Pd-I forms it is pretty rapidly reduced by NEt3 to Pd0, but I could easily be wrong on that.

Does the minor (desired) product convert to the major one over time? Or does the product distribution remain constant?

You could probably solve the problem by using e.g. TBS-ethylene, but sounds like you've got around it by making the conditions a little more gentle anyway.

[kevin_lofgren]

the way the products are displayed in the article I believe the distribution remains constant. If the silicon atom is protonated then the only problem I'm facing is the way the silly group would be eliminated.