Which of the following represents the rate-determining trans…

Which of the following represents the rate-determining transition state for the formation of the MAJOR product in the reaction shown below? Note: The relative reaction rates of 1° H : 2° H : 3° H are 1 : 4 : 5, respectively. Both chain propagation steps of the reaction are exothermic.

The reaction shown (reaction 1) below is a so-called semipin…

The reaction shown (reaction 1) below is a so-called semipinacol rearrangement. Silver nitrate is added to the reactant in order to precipitate silver iodide and produce a carbocation. Draw the most stable chair conformation of the starting material on your scratch paper and answer the following questions. After the formation of the initial carbocation, a rearrangement takes place. The migrating group or atom must be anti to the leaving group (the bond containing the migrating electron pair will be drawn parallel to the carbon-iodine bond in your chair conformation). Would you expect a hydride shift or a ring contraction to occur? [rearrangement] Which of the following (A-D) depicts the expected major product of reaction 1? [product1] The outcome of the reaction discussed in this problem is highly dependent on reactant stereochemistry. Consider reaction 2 (shown below) and answer the following questions. In the most stable chair conformation of the reactant (tert-butyl is equatorial), is there a migrating group (hydrogen atom, alkyl group, or C-C ring bond) that is anti to the leaving group? [anti] Which of the following (E-F) might reasonably form as the major product of the reaction? [product2]