Hydroformylation Exercises

Some of these questions are explained in the assigned readings, so please make sure you have done the reading before working out your answers.

1. Draw a reasonable transition-state structure for the regioselectivity-determining step in the accepted mechanism for hydroformylation catalysis involving RhL₂(H)(CO).
2. Is the transition-state structure from the preceding question an example of a three-center transition state? Explain.
3. What is the change in dⁿ count and total electron count accompanying the above transformation?
4. In hydroformylation, what is the name of the reaction type involved in ultimate release of the aldehyde product from the metal center?
5. What is the molecule that is generated initially upon reaction of H₂ with Co₂(CO)₈?
6. What are the changes that take place in ligand bond number, dⁿ count, and total electron count accompanying the migratory insertion step of hydroformylation catalysis involving RhL₂(H)(CO)?
7. What is the definition of linearity in hydroformylation?
8. High linearity is generally desirable in the context of hydroformylation. What is the bidentate phosphine ligand parameter that has been correlated with the degree of product linearity?
9. "Syngas" is short for "synthesis gas"; what is it composed of?
10. In considering the space-filling properties of PR₃ and P(OR)₃ ligands, Tolman gave a definition of cone angle, θ, that could be correlated with reactivity properties. Draw a picture that illustrates the definition of cone angle for PMe₃.
11. Upon what reaction and physical measurement was based Tolman's electronic parameter, ν, for assessing the electron releasing/accepting properties of PR₃ and P(OR)₃ ligands?
12. In Calderazzo's experiment involving ¹³C isotopic labeling of a single cis CO ligand in MeMn(CO)₅, formation of a product with ¹³CO trans to the ligand L would be indicative of which mechanism for formation of the acyl?