Both trans and cis isomers of 3-methoxycyclohexanol are found as components of a group of antibiotics known as macro ides. Both 3-methoxycylohexanols are chiral. However, one diastereomer reacts with methyl iodide and base to give optically the active 1, 3-dimethoxycylohexane. "e other diastereomer gives a raceme mixture of optically active 3,3-dimethoxycyclohexanes. Illustrates the structure that account for the stereochemistry of these reactions.