Question

Consider the circled hydrogens. Which of the following terms best describes those atoms? (Select all that apply.) Assume no other chiral species are present. constitutionally equivalent chemically equivalent homotopic enantiotopic diastereotopic

Answer 1

Identical or Homotopic: When the hydrogens attached from same carbon or same type of carbon that is identical are called homotopic н H CH3 Н,С Н,С CH3 Enantiotopic: When replacements of each hydrogen give an enantiomeric mixture then both hydrogens are called as Enantiotopic н Cl Н Н a Cl Н H Н,С E-alkene Н,С HЬ H Cl н Н,С H Н,С Z-alkene Different groups Cl H На Н .CH3 .CH3 Н.С C Н, Н.С Н, .CH3 CH3 Н,С Н.С Н, Н, Different groups

Diastereotopic: When the hydrogens attached to that carbon which is attached an electronegative group. In other words, a- atom of Diastereotopic hydrogens is electronegative atom. Cl Н Cl Н H CI NH2 E-alkene "NH2 H2C NH2 Н,С Z-alkene Н.С H b H Н. Cl н Cl Cl NH2 NH2 Н.С E-alkene НС Z-alkene Cl Cl H H Ha Н Cl CH "NH2 HN Н,С NH2 Н,С н Cl H н Cl S R 'NH2 H2N CH3 Н.С NH2 Н.С Answer: Enantiotopic. Cl H н a H Н,С E-alkene H Н,С Hb H Cl н С Н.С Н.С H Z-alkene Different groups