See image — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

Step 1 - Identify the two double bonds in the molecule. Double bond 1: The exocyclic alkene on the left side of the cyclopentane ring. Its two carbons bear: left carbon has NC (cyano) and CH2NH2 (aminomethyl); right carbon has the cyclopentane ring carbon and CN (cyano). Double bond 2: The exocyclic alkene on the right side of the cyclopentane ring. Its two carbons bear: one carbon (exo) has COOH and CH2OH; the other carbon is part of the cyclopentane ring. Step 2 - Assign priorities for Double Bond 1. Left carbon substituents: NC (cyano, C≡N, attached via C) vs CH2NH2 (attached via C). For NC: the nitrile carbon is triple-bonded to N, so phantom atoms give C(N,N,N). For CH2NH2: the carbon is bonded to N,H,H. Comparing: C(N,N,N) > C(N,H,H), so NC > CH2NH2. Therefore NC has higher priority (1) and CH2NH2 has lower priority (2) on the left carbon. Right carbon substituents: CN (cyano attached via C, same reasoning as above: C(N,N,N)) vs cyclopentane ring carbon (C bonded to C,C,H). Comparing C(N,N,N) vs C(C,C,H): N > C, so CN > cyclopentyl ring. Therefore CN has higher priority (1) and ring carbon has lower priority (2) on the right carbon. Configuration: NC (priority 1, left) is on the same side as CN (priority 1, right) — both are on the same face of the double bond as drawn (NC upper-left, CN lower-right are on opposite sides). Looking at the structure: NC is on the top-left and CN is on the bottom-right — they are on OPPOSITE sides. Therefore the two higher priority groups are on opposite sides → E configuration. Step 3 - Assign priorities for Double Bond 2. Exo carbon substituents: COOH (C bonded to O,O,H by phantom atom expansion: C(O,O,O)) vs CH2OH (C bonded to O,H,H: C(O,H,H)). COOH > CH2OH. Higher priority = COOH (top). Ring carbon substituents: the two ring carbons (the two CH2 groups of cyclopentane connecting back). Both sides of the ring from this carbon lead back through CH2 chains. One path leads to the other exocyclic double bond carbon (which bears CN and aminomethyl via the other alkene). The substituent going toward the other double-bond-bearing carbon has higher substitution. The ring carbon has two ring-CH2 paths; one leads to C bearing two CN groups and aminomethyl (higher priority), the other leads to a plain CH2. Higher priority = the ring path leading toward the more substituted carbon. The COOH group (higher priority on the exo carbon) and the higher-priority ring substituent: by analysis of the drawing, COOH is on top and the higher-priority ring path is also on the same side → they are on opposite sides of the double bond → E configuration. Step 4 - Both double bonds are E. Options (a) E (only one double bond described), (b) Z, (c) E, E, (d) Z, Z. Since both double bonds are E, the answer is E, E. Why other options fail: - (a) E: describes only one double bond, incomplete. - (b) Z: incorrect, priorities place higher groups on opposite sides for both bonds. - (d) Z, Z: incorrect assignment of configurations. Therefore, the correct answer is C.