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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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‚ on June 16‚ 1897‚ and died August 26‚ 1987 (1). Wittig discovered the route to alkenes through ylide molecules (1). Wittig was educated
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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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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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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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INTRODUCTION The study of the Wittig Reaction is important because it is often used to form alkenes from carbonyl compounds. The purpose of this experiment is to isolate the trans‚ trans-1‚4-diphenyl-1‚3-butadiene‚ which is formed by a Wittig reaction along with the cis‚ trans isomeric diene. The reaction is carried out in two steps. First the Wittig salt is obtained through a simple nucleophilic displacement of chloride ion by triphenylphosphine. When treated with base‚ the Wittig salt forms a ylide which
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Grignard Reaction: Synthesis of Triphenylmethanol Dominic DiRaimo Lab Partners: Roxana Hernandez Somata Thach TA: Sreya Mukherjee December 5‚ 2013 Introduction Grignard reagents are good nucleophiles as well as strong bases (Weldegirma). It allows compounds to react with acidic compounds‚ therefor is must be free from acids as well as water during the desired reaction. Another important aspect of Grignard reagent is that refluxing is necessary to
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Examples of synthesis reactions: 1. Metal + oxygen → metal oxide EX. 2Mg(s) + O2(g) → 2MgO(s) 2. Nonmetal + oxygen → nonmetallic oxide EX. C(s) + O2(g) → CO2(g) 3. Metal oxide + water → metallic hydroxide EX. MgO(s) + H2O(l) → Mg(OH)2(s) 4. Nonmetallic oxide + water → acid EX. CO2(g) + H2O(l) → ; H2CO3(aq) 5. Metal + nonmetal → salt EX. 2 Na(s) + Cl2(g) → 2NaCl(s) 6. A few nonmetals combine with each other. EX. 2P(s) + 3Cl2(g) →
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