It is essential that the Cl and O can adopt the proper orientation with respect to eachother. This is best studied in cyclic compounds. We take cis-2-chlorocyclohexanol and trans-2-chlorocyclohexanol as an example. First we have a look at the compound themselves. In a previous exercise we have discussed the stereochemistry of 1,2-disubstituted cyclohexanes, and the axial/equatorial interchange during the chair-to-chair ring flip. For the two compounds mentioned above, this process can be seen here again. Note the relative stability of the conformational isomers. cis-2-chlorocyclohexanol trans-2-chlorocyclohexanol Next, we attempt the substitution reaction, in both the cis and the trans isomer, with the O- in axial position. Have a look, and answer the questions below. cis-2-chlorocyclohexanol anion trans-2-chlorocyclohexanol anion Questions You may use English or Dutch In trans-2-chlorocyclohexanol, the energy difference between the axial/axial and the equatorial/equatorial conformation is very small, e.g. when compared to dimethylcyclohexane. Why could that be? Which isomer shows the expected epoxide formation? Describe what happens in the other isomer. Type your name(s): and your answers!
First we have a look at the compound themselves. In a previous exercise we have discussed the stereochemistry of 1,2-disubstituted cyclohexanes, and the axial/equatorial interchange during the chair-to-chair ring flip. For the two compounds mentioned above, this process can be seen here again. Note the relative stability of the conformational isomers.