Question:

M and N in the given reaction scheme are (Simmons–Smith on the alkene, then OsO\(_4\)/NMO): 

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Simmons–Smith on allylic alcohols is {directed}: the cyclopropane forms {syn} to the OH-bearing face. OsO\(_4\) (with NMO) adds {syn} to alkenes, giving {cis}-1,2-diols. Combine directing/syn rules to set relative configurations in sequences.
Updated On: Aug 29, 2025
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Solution and Explanation

Step 1: Simmons–Smith (CH\(_2\)I\(_2\), Zn–Cu). Allylic alcohols direct Simmons–Smith cyclopropanation to the same face as the OH (chelation of the carbenoid to the alcohol). Therefore, the double bond of the cyclohexene is converted to a fused cyclopropane (bicyclo[4.1.0]heptane framework) with the newly formed CH\(_2\) group syn to the existing OH. This matches the structure of M shown in option (C).
Step 2: OsO\(_4\)/NMO dihydroxylation. Osmium tetroxide adds syn across the C=C to give a vicinal cis-diol. Applying this to the substrate furnishes a triol in which the two newly introduced OH groups are on the same face (cis to each other), as depicted for N in option (C).
Step 3: Eliminate other options.
(A) and (D) depict cyclopropanation from the face anti to the directing OH (contrary to Simmons–Smith OH-directing effect).
(B) and (D) show triol stereochemistries inconsistent with syn dihydroxylation.
Hence, (C) correctly represents both M and N.
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