Absolute stereochemistry of the given compound is: · ABC26OR0768
Subject: Organic Chemistry · Chapter: Stereochemistry · Topic: Stereochemistry – General · Exam: GATE 2000-2022 · Marks: 2 · Difficulty: Easy
Absolute stereochemistry of the given compound is: 
(a)$4a\text{-}\mathrm{S}, 8a\text{-}\mathrm{R}$
(b)$4a\text{-}\mathrm{R}, 8a\text{-}\mathrm{S}$
(c)$4a\text{-}\mathrm{S}, 8a\text{-}\mathrm{S}$
(d)$4a\text{-}\mathrm{R}, 8a\text{-}\mathrm{R}$
Answer
Answer: A ✓ checked by 4AB · confidence medium
Explanation
C-8a: C-1 (C=O; O,O,C) > CHO (O,O,H) > C-4a (O,C,C) > C-8 (C,H,H). With CHO hashed (away) and the ring bonds in the plane, the 3-D arrangement gives 8aR. C-4a: OH > C-8a (C,C,C) > C-4 (its next atom C-3 is sp²) > C-5. With OH hashed (away), the arrangement gives 4aS. Hence 4aS, 8aR — option (a).
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