Substituents on Aromatic Aldehydes and How They Affect E/Z Selectivity in the Wittig Reaction

Abstract:The Wittig reception is a nucleophilic improver in which an alkene is prink as a product. both the E and Z isomers of the alkene result. Substituents on the aromatic aldehyde incite the E/Z residuum of products that form. In this experiment, a nitro gathering was used as the substituent in the ortho, meta and para positions, with benzaldehyde as the control. each of the four aldehydes reacted with (carbethoxym ethyl radicalene) triphenylphosphorane to contract ethyl cinnamate, ethyl-3-(2-nitrophenyl)acrylate, ethyl-3-(3-nitrophenyl)acrylate, and ethyl-3-(4-nitrophenyl)acrylate. The prediction was the proximate the substituent was to the aldehyde, the greater the proportionality of E/Z isomers; benzaldehyde was predicted to result in the most similar proportion of E/Z isomers. The proportions of E/Z isomers were cookd by utilise the nuclear magnetic resonance spectra obtained. A percent conversion was overly obtained. Ethyl-3-(2-nitrophenyl)acrylate had a ratio of 9.03:1, ethyl-3-(3-nitrophenyl)acrylate had a ratio of 5.2:1, ethyl-3-(4-nitrophenyl)acrylate had a ratio of 1:1 and ethyl cinnamate had a ratio of 9.3:1. The results for the compounds pretermit ethyl cinnamate supported the supposition that the ratio would be closer to 1:1 as the substituent moved further from the carbonyl. opening:The manipulation of this experiment is to determine how a nitro theme on benzaldehyde affects the stereoisomer system of the alkene make in a Wittig reply. The nitro group is substituted in the ortho, meta, and para positions, and benzaldehyde serves as a control. The ylide used is (carbethoxymethylene) triphenylphosphorane.

with the physical exertion of NMR spectroscopy, the products of the reactions will be study to gain a ratio of E /Z isomers. Reaction Equations:Ethyl cinnamate from BenzaldehydeEthyl-3-(2-nirophenyl)acrylate from O-nitrobenzaldehydeEthyl-3-(3-nitrophenyl)acrylate from M-nitrobenzaldehydeEthyl-3-(4-nitrophenyl)acrylate from P-nitrobenzaldehydeIn 1954, Georg Wittig, a German chemist, discovered the Wittig Reaction. In 1979, Wittig won a Nobel regard in Chemistry due to the Wittig Reaction?s synthetic emf to form a intermixture of different alkenes. Today, this... If you want to corroborate a full essay, rescript it on our website: Ordercustompaper.com

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