Problem set 7; Chem. 127/227, Fall quarter 2007 1. (a) Formulate a mechanism illustrating the E 2 elimination sequence that places the π-bond between C2 and C3, starting from the substrate shown below. Pay particular attention to stereochemistry. Br 2 3 1 (b) Does the structure of the product correspond to an E- or to a Z-alkene? Provide a name that is consistent with IUPAC rules of nomenclature. (Note that your mechanism must be formulated so that it accounts for the stereochemical outcome.) (c) Formulate a rate expression for the process. 2. Now look at the β-hydroxy aldehyde shown below, the product of an aldol condensation. H OH O (a) Use an aldol condensation to illustrate how the substance could be synthesized. (b) β-Hydroxy aldehydes, ketones, ester, nitriles (etc.) often undergo β-elimination, leading to the formation of an α , β-unsaturated adduct. Using hydroxide ion as the base, illustrate the elimination process, and provide the structure of the product(s) derived from the
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