The purpose of this experiment was to perform a wittig reaction‚ the horner-emmons wittig specifically‚ reacting an aldehyde with an ylide to make an alkene. This particular variation of the wittig reaction has several advantages: It gives only the trans product; it uses a much milder base that is easier to handle; and it gives a water soluble byproduct which is easy to separate from the product. The reason that these advantages occur is a change in the structure of the ylide. Instead of a tripheylphosphine
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Experiment 3: Wittig Reaction Introduction This experiment performs a modified Wittig reaction using a phosphorus-containing Hornes-Emmons-Wittig reagent to generate an enolate anion of trimethyl phosphonoacetate instead of a phosphorus ylide. The methyl trans-4-methoxy cinnamate produced is then analyzed using melting point and 1H NMR spectroscopy. Theory The Wittig reaction prepares alkenes from carbonyl compounds by attacking a phosphorus ylide with a nucleophilic carbon atom stabilized by
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REPORT! EXPERIMENT#5‚6! MANPREET KAUR KHAIRA! LAB PARTNER: VIAN RAIES! The purpose of this lab exercise was to perform the bromination of (E)-1‚2-diphenylethene (trans-stilbene) by addition reaction in which bromine was added across the double bond to yield a vicinal dibromide. The next step was to perform a double elimination reaction by product gained to synthesize an alkyne‚ that is‚ 1‚2-diphenylacetylene. The two major techniques used in this lab were TLC analysis and UV-vis spectroscopy. TLC
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experiment is to synthesize trans-9-(2-phenylethenyl) anthracene from benzyltriphenylphosphonium chloride and 9-anthraldehyde through the reaction mechanism recognized as the Wittig Reaction. The Wittig Reaction allows the chemist to synthesize phosphoranes in the lab with relative ease. A more recent and inexpensive version of the reaction is the Wittig-Horner reaction (1). ABSTRACT Georg Wittig was a German chemist and Nobel Prize winner in 1979 for the Wittig reaction (1). He was born in Berlin
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Discovered by Georg Wittig in 1954‚ the Wittig reaction is a robust organic synthesis method for preparing stereospecific alkenes. In general‚ Wittig reactions involve an aldehyde or ketone and a Wittig reagent (triphenylphosphonium ylide) and result in the formation of an alkene product and triphenylphosphine oxide (side product). Stereospecific alkene products can be synthesized by adjusting the reaction reagents and conditions. In the 60 years since the Wittig reaction was discovered‚ many articles
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Experiment 5: Wittig Reaction Purpose The purpose of this experiment is to synthesize trans-9-(2-phenylethenyl) anthracene using a wittig reagent formed by reacting phosphonium chloride with base. Experimental In a reaction tube‚ (0.200g) benzyltriphenyl phosphonium chloride‚ (0.115g) anthraaldehyde‚ and (.6ml) dichloromethane (DCM) is mixed together with a stir bar. We stirred the mixture rapidly and added (0.26ml) of a 50% NaOH solution dropwise. The mixture was stirred for 20-30
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Bromination of trans- Stilbene to form 1‚2- Dibromo- 1‚2-diphenylethane Abstract 1‚2-dibromo-1‚2-diphenylethane was produced by the bromination of trans-stilbene through the addition of hydrobromic acid (HBr) and hydrogen peroxide (H2O2). This experiment was a greener bromination of stilbene because bromine was generated in situ and ethanol was used as the solvent. The melting point (243.30°C)‚ mass (.427g)‚ and percent yield (45.54) of the crystals were recorded. The FTIR
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SYNTHESIS OF TRANS-9-(2-PHENYLETHENYL) ANTHRACENE (A WITTIG REACTION) Introduction: The purpose of this experiment is to convert carbonyl compounds to alkenes using Wittig reaction. In this case we will be synthesizing Trans-9-(2-phenylethenyl) anthracene from benzyltriphenylphosphonium chloride and 9-anthraldehyde. We will also aim to obtaining a high percent yield and purity for the synthesis of Trans-9-(2-phenylethenyl) anthracene. The mechanism for this reaction goes thus:
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Though cis-platin is highly effective‚ its counterpart trans-platin is counterintuitively not (7). Trans-platin is highly reactive with the environments that lead to reaching the DNA‚ and this reactivity results in the totality of the administered compound becoming deactivated prior to reacting with the DNA (9). Also the DNA lesion caused by cis-platin on the 1‚2 intrastrand crosslinks between adjacent purines is an act that trans-platin cannot do when looking from a stereochemical perspective (9)
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Wittig Reaction and Photoisomerization Abstract: For this laboratory experiment stilbene was produced through a Wittig reaction with benzyltriphenyl phosphonium and benzaldehyde producing a form of stilbene (Figure 1). This reaction favored a crude Z-Stilbene crystal product over its E counterpart. When Z-Stilbene underwent photoisomerization with iodine for 1 hour it reconfigured almost exclusively into its more stable counterpart E-Stilbene. The reaction produced very low yield of 6.3% due
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