Chemistry - STEREO ISOMERISM Question with Solution | TestHub

Ans. A and B : diastereomers; B and C : diastereomers; A and D : enantiomers; A and C : diastereomers.

Sol. All four are 2,3,4-trimethylpentanal (three stereocentres C-2, C-3, C-4). (A) has all three methyls in front; (D) has all three behind, i.e. every centre inverted : enantiomers. (B) inverts only C-2, (C) inverts C-2 and C-3 relative to (A); pairs differing at some but not all stereocentres are not mirror images : diastereomers.