5106

Addition of methylmagnesium bromide to 2-methylcyclohexanone followed by iodine-catalyzed dehydration of the resulting alcohol gave three alkenes in the ratio A:B:C = 3:31:66. Each isomer gave a mixture of cis - and trans-1,2-dimethylcyclohexane on catalytic hydrogenation. When the alkene mixture is heated with a small amount of sulfuric acid, the ratio of A:B:C is changed to 0.0:15:85. Assign structures to A, B, and C, and discuss your rationale in terms of the appropriate kinetic and thermodynamic principles.

5134

Write the equation for the expected olefin product(s) from the acid-catalyzed dehydration of 2-methylcyclohexanol, indicating which product(s) would be expected to predominate and why.

5319

The enzyme enolase catalyzes the following reaction:

When (2R,3R)-2-phosphoglycerate-3-d was used as the substrate, the E isomer of phosphoenolpyruvate-3-d was produced. Is the stereochemistry of elimination syn or anti ?

5322

An unknown compound, A, C₆H₁₀O, m.p. -16°, b.p. 156° was almost insoluble in water. When treated with hydrogen and a platinum catalyst it gave a new compound, B, C₆H₁₂O. When compound B was heated with acid, it gave a new substance, C, C₆H₁₀. Finally, when C was treated with hydrogen using a platinum catalyst it yielded cyclohexane. Identify the structures of the lettered compounds; indicate the index of hydrogen deficiency.