Structures with Two Stereogenic Centers Dimethyl Cyclohexanes

Cyclic Structures with Two Stereogenic Centers Dimethyl Cyclohexanes 

2- disubstituted cyclobutane with two equivalent chiral centers has only three diastereomers, one of which is a meso compound. 

The cis and trans isomers of 1,4-dimethylcyclohexane are achiral because each has a plane of symmetry. 

The mirror images of cis-, 2-dimethylcyclohexane are not superimposable. However, chair—chair interconversion is very fast, so the enantiomers cannot be separated. 

What is the absolute configuration of muscone, a compound used in perfumes to provide a musk odor  

---