Q18 · CSIR-NET Chemistry, June 2018

Paper: CSIR-NET June 2018 · Subject: Organic Chemistry · Chapter: Reagents, Reaction Mechanisms & Named Reactions · Topic: Reagents, Reaction Mechanisms & Named Reactions – General · Marks: 2 · Difficulty: Medium

Structure of the intermediate A and the final product B in the following reaction sequence are Question structure 1 of 7, ABC26OR0374 Question structure 2 of 7, ABC26OR0374 Question structure 3 of 7, ABC26OR0374 Question structure 4 of 7, ABC26OR0374 Question structure 5 of 7, ABC26OR0374 Question structure 6 of 7, ABC26OR0374 Question structure 7 of 7, ABC26OR0374
(a)Option (a) structure 1 of 3, ABC26OR0374 Option (a) structure 2 of 3, ABC26OR0374 B = Option (a) structure 3 of 3, ABC26OR0374
(b)Option (b) structure 1 of 3, ABC26OR0374 Option (b) structure 2 of 3, ABC26OR0374 B = Option (b) structure 3 of 3, ABC26OR0374
(c)Option (c) structure 1 of 3, ABC26OR0374 Option (c) structure 2 of 3, ABC26OR0374 B = Option (c) structure 3 of 3, ABC26OR0374
(d)A = Option (d) structure 1 of 2, ABC26OR0374 B = Option (d) structure 2 of 2, ABC26OR0374
Answer
Answer: A ✓ checked by 4AB · confidence medium
Explanation
Pd(0) opens the vinyl epoxide to a π-allyl with the alkoxide anti to Pd; the malonate attacks anti to Pd, so nucleophile and OH end up cis (A). m-CPBA is then directed by the free hydroxyl to the syn face, giving the epoxide cis to OH (B) — (a).

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