Mechanism of orgonometallic reactions

Question

Question 1: Sketch the transition state for the first step in oxidative addition of a benzyl halide and a square planar complex ML₄.

Question 2: Describe the following. The cis isomer of L₂Pd(Et)₂ decomposes instantly to give butane, however the trans isomer produces a 1:1 mixture of ethene and ethane.

Question 3: The reaction of L₂Pd(Me)₂ with PhC*HDBr produced PhC*HDMe. Determine the other product and do you expect retention or inversion at chiral carbon?

Question 4: SO₂ can insert into an LnM-CR₃ bond. The reaction is thought to proceed by an SE₂ pathway to form an ion pair, [LnM]⁺[OS(O)R]^–. Collapse of the ion pair produces the O-sulfinate (formally a 1,2-insertion of SO₂), which can re-arrange to the S-sulfinate (formally a 1,1-insertion of SO₂). Draw the transition state, the ion pair, and the O- and S-sulfinates.

Question 5: Give a mechanism for the reaction:

LnZr–H + E–2-butene → LnZr–CH₂CH₂CH₂CH₃

Question 6: Binding of Cr(CO)₃ to an achiral arene:

gives a chiral complex. Describe this. What about for meta- and para- substituted arenes? How might this be helpful?