Chapter 32, Problem 2ASA

1. The following conversion includes chemistry we have covered very recently, some chemistry from last term, and chemistry from the first chapter of this unit. Provide curly arrows and an explanation for this mechanism. Use the reagents in the order given. You do not need any other reagents. 1. NaOEt OEt 2.

COOEt COOEt Step 1 Step 2 Step 3 COOEt COOEt COOH Step 6 OH Step 4 Step 7 (racemic) cyclizes under conditions (8) OTS Step 5 Step 8 ОН OH (racemic) Frontalin (racemic) Shown above are the steps in one of the several published syntheses of Frontalin, a pheromone of the western pine beetle. From the choices provided, show the reagents and conditions by which step 3 of this synthesis might be accomplished. List the reagent(s) in order that will accomplish this transformation. No more than 4 steps are required. List your answer as a single letter (single-step transformation) or a series of letters (multi-step transformation) with no commas separating them. For example, "ab" corresponds to: 1. Eto Na+ 2. NaOH, H₂O NOTE: The order in which you list your letters matters! Reagents: a. Eto Na* g. NaCN b. NaOH, H₂O h. SOCI₂ c. H3O+, heat i. (CH3)2CuLi, ether, -78°C d. LiAlH4 j. H₂O e. p-TsCI, pyridine k. RCO3H f. Br I. H3O+ 1,024

K ← nationa Login - Paymentivet MapQue Draw the major product of this reaction. Ignore inorganic byproducts and the carboxylic acid side product. N 1. excess LiAlH4 2. H₂O ✓ W a