Make a reaction flowchart (roadmap diagram), as in previous problems, to organize the information provided to solve this problem. An optically active compound A (assume that it is dextrorotatory) has the molecular formula C7H11Br. A reacts with hydrogen bromide, in the absence of peroxides, to yield isomeric products, B and C, with the molecular formula C7H12Br2. Compound B is optically active; C is not. Treating B with 1 mol of potassium tert-butoxide yields (+)-A. Treating C with 1 mol of potassium tert-butoxide yields ±-A. Treating A with potassium tert-butoxide yields D (C7H10). Subjecting 1 mol of D to ozonolysis followed by treatment with dimethyl sulfide (Me2S) yields 2 mol of formaldehyde and 1 mol of 1,3-cyclopentanedione. Propose stereochemical formulas for A, B, C, and D and outline the reactions involved in these transformations.

1, 3-Cyclopentanedione