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Consider the following reaction sequence: 2-methylhexane-1,5-diol PCC (excess) P [ H ⁺] Ethylene glycol (1 eq.) Q [ 2. H ₃ O ⁺] 1. CH ₃ MgBr (excess) R NaBH ₄, EtOH S The number of chiral carbon atoms in compound S is _______.

Correct answer

1

Step-by-step solution

Step 1: PCC is an oxidizing agent that converts primary alcohols to aldehydes and secondary alcohols to ketones. Thus, 2-methylhexane-1,5-diol is oxidized to 2-methyl-5-oxohexanal (P). Step 2: Aldehydes are more reactive towards nucleophilic addition than ketones. Treatment of P with 1 equivalent of ethylene glycol in acidic medium selectively protects the aldehyde group, forming an acetal (Q). Step 3: The Grignard reagent ( CH ₃ MgBr ) attacks the unprotected ketone group, converting it into a tertiary alcohol. Th

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