Compounds 1 and 2 can be described as:

Question

Quizplus · Accepted Answer

11ecba2d_128d_a4c1_a3bf_3384cef2518f_MD0008_00 Isomers are compounds that have the same molecular formula but a different arrangement of atoms. Conformational isomers are structures that have the same connectivity and can be interconverted by the rotation of σ bonds. Because conformational isomers are identical except for bond rotations, they are the same compound. Six-membered rings can be depicted in two different ways: as a wedge-dash projection or a chair conformation. In wedge-dash projections, wedges indicate the substituent is up and above the ring, and dashes indicate the substituent is down and below the ring. Substituents can be either axial or equatorial in a chair conformation. However, axial and equatorial do not dictate whether the substituent is up and above the ring or down and below the ring. The wedge-dash projection of Compound 1 shows the -OH and the -CH₃ both on a dash (down). Likewise, the chair conformation of Compound 2 shows the -OH and -CH₃ as equatorial down. To represent this wedge-dash projection as a chair conformation, both substituents can be shown as axial down. A chair flip puts the substituents in an equatorial down position (still on the same side of the ring), yielding an identical structure to Compound 2. Because these compounds have the same connectivity and can be interconverted from one to the other through bond rotations (via chair flip), they are conformational isomers. (Choice A) Enantiomers are nonsuperimposable mirror images in which all stereocenters are inverted. The stereocenter configurations in Compounds 1 and 2 are identical, and therefore cannot be enantiomers. (Choice B) Diastereomers are stereoisomers in which at least one, but not all, stereocenters are inverted. Because none of the stereocenters in Compounds 1 and 2 are inverted, they cannot be diastereomers. (Choice D) Compounds 1 and 2 have the same molecular formula and the same connectivity, so they are not constitutional isomers. Educational objective: Conformational isomers are structures that have the same formula and connectivity, and can be interconverted by the rotation of σ bonds. Because conformational isomers are identical except for structural bond rotations, they are the same compound.

Compounds 1 and 2 Can Be Described As