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Give explanation of the correct option and explanation of the incorrect options.

The diene lactone shown in part (a) has one electron-donating group (¬OR) and one electron-withdrawing group(C“O). This diene lactone is sufficiently electron-rich to serve as the diene in a Diels–Alder reaction.(a) What product would you expect to form when this diene reacts with methyl acetylenecarboxylate, a strong dienophile?

3c）Referring to the intermediates you drew in problem below explain in detail why no meta product is obtained in the Friedel-Crafts alkylation of chlorobenzene. Draw all pertinent resonance structures to support your argument.

Using one or more of the following compounds as starting materials or products illustrate, with an example, each of the following type of pericyclic reactions. Your answer should include curved arrow mechanisms. (i) a disrotatory thermal electrocyclic reaction (ii) a conrotatory photochemical electrocyclic reaction (iii) a [4+2] cycloaddition (iv) a [3,3]-sigmatropic rearrangement

(a) Write the products of following reactions. Give mechanism with proper stereochemistry? (2 x 2.5 = 5) (ii) Me Δ Δ CN

(a) In an acid-catalyzed hydration, one of the following 10 carbon alkynes is expected to produce a single hydration product? Select the correct alkyne and draw the structure of the hydration product that is formed from this alkyne. (I) 2-decyne; (II) 3-decyne; (III) 4-decyne; (IV) 5-decyne; (V) none of these will give a single hydration product. (b) The reaction shown below gives Compound X as the major product. The mass spectrum of X is shown. Br2, H20 Compound X 100 - MS-IW-5644 80 60 40 - 20 - 20 40 60 80 100 120 140 160 180 200 220 m/z Considering the reactions of alkynes and the MS data, de duce which of following structures corresponds to X: Br Br HO, IV V I II II Support your answer with a reaction mechanism for fomation of X and identification of relevant peaks in the mass spectrum. 12 Relative Intensity

Following is an equation for hydroperoxidation of cumene. light + O2 for HOO- Cumene Cumene hydroperoxide Propose a radical chain mechanism for this reaction. Assume that initiation is by an unspecified radical, R.

The reaction between singlet oxygen and limonene (below) is often used to characterize the behaviour of singlet oxygen as an electrophile rather than an initiator for a free radical mechanism. HOO Limonene Scheme 1 (a) Since singlet oxygen is a high energy state, the formation of a diradical seems plausible: 0=0* Propose a sequence of steps for this diradical reacting with limonene and explain why the major product, which is obtained (Scheme 1), does not support this reaction mechanism

(c) Compound 2F shown below is a tetra-substituted cyclooctatetraene. After heating 2F at 160 degree for 6 hours, researchers observed the formation of an isomer of 2F. Draw the isomer structure and provide a plausible mechanism to explain the formation of the isomers. 2F