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46 Cards in this Set
- Front
- Back
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Diethyl ether
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Ethoxy penatane?
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Name the following compound? a. unsystematic name b. IUPAC name
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a. Methyl Phenyl Ether / b. Methoxy Benzene
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Compare and explain BP of the following compounds?
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Ethanol : Highest BP due to hydrogen bonding / Dimethyl ether: middle BP, possess permenent dipole moment => dipole-dipole interaction / Propane: lowest BP, possess only london dispersion forces
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Dioxane? (as solvent)
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Usually refers to 1,4-dioxane
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Why Grignard reagent is usually made in ethers (diethyl ether)?
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Ethers can stabilize the resulting Grignard reagent
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What are crown ethers?
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cyclic polyethers. For example
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What is 12-Crown-4?
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Crown ether with 4 oxygen and totally 12 atom(8C+4O) on ring
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What is 15-Crown-5?
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Crown ether with 5 oxygen and totally 15 atom(10C+5O)
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Crown ether solvates K+ and therefore F- is free to do SN2 reaction
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Describe general form of Williamson ether synthesis?
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Preparation of ethers from alcohols and alkyl halides by a SN2 reaction
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For Williamson ether synthesis what should be taken into account when choosing substrates?
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Since it is SN2 reaction, Alkyl halide cannot be tertiary and it will also go with difficulty with secondary. The most efficient is when Alkyl halide is primery.
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Synthetize the following Ether via Williamson ether synthesis reaction?
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Since it is SN2 reaction, Alkyl halide cannot be tertiary
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alkoxymercuration-demercuration (Anti , markovnikov)
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Explain Acidic Cleavage of Ethers?
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Two successive (protonation and SN2 attack of halide) which results in the formation of two Alkyl halide
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Acidic cleavage of Ethers (but The phenol is not further converted into a halide, because neither SN2 nor SN1 processes are efficient at sp2-hybridized centers)
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What are Oxiranes?
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cyclic ethers containing a three-membered ring system
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Name the following epoxide? a. systematic name b. unsystematic name
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a. 3-Ethyl-2-methyl-2,3-epoxy pentane (look at the bottom picture) / b.1,1-Diethyl-2,2-dimethyloxirane (look at the front card numbering)
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Name the following compound?
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1,2-epoxy-cyclohexane
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Show stereoisomerism in the product
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Product? Show correct stereoisomers if there is any?
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Epoxidation by peroxides is stereospecific (Cis alkene -> cis-exposide / Trans alkene -> trans epoxide)
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1). Formtion of halohydrin 2).SN2 reaction result in the formation of epoxide (via deporotonation of OH group and then O- will attack the carbon to kick Br out)
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Epoxidation is stereospecific (Cis alkene -> cis-exposide / Trans alkene -> trans epoxide)
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Epoxidation is stereospecific (Cis alkene -> cis-exposide / Trans alkene -> trans epoxide) / in the case of fromation of a chrial center both enantiomers are formed because epoxide ring is formed concerted and syn so it can be form from the top-side or bottom-side of alkene
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What is DET?what is it usedfor?
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Diethyltartrate / used as chiral chatalyst for chiral epoxidation
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generally How we can predict the stereochemistry of Sharpless asymmetric epoxidation (a reaction similra to the below reaction)?
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To predict the product of a Sharpless asymmetric epoxidation , orient the molecule so that
the allylic hydroxyl group appears in the upper right corner (look at the Figure). When positioned in this way, ( +)-DET gives epoxide formation above the plane, and (–)-DET gives epoxide formation below the plane. |
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Epoxide cleavage in basic condition (SN2-like reaction, attack to less substituted carbon)
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Epoxide cleavage in basic condition (SN2-like reaction so attack to less substituted carbon and inversion of configuration at the center of attack)
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Acidic cleavage of epoxide ring (in presence of H3O+ gives anti dihyration)
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Epoxide cleavage in Acidic condition: it goes SN1-like so, if there is a 3o carbon it will be attacked otherwise the less substituted if there is not tertiary
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Acidic cleavage of epoxide ring (in presence of H3O+ gives anti dihyration)
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Epoxide cleavage in Acidic condition: it goes SN1-like so, if there is a 3o carbon it will be attacked otherwise the less substituted if there is not tertiary
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Epoxide cleavage in Acidic condition: it goes SN1-like so, if there is a 3o carbon it will be attacked otherwise the less substituted if there is not tertiary
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Epoxide cleavage in Acidic condition: it goes SN1-like so, if there is a 3o carbon it will be attacked otherwise the less substituted if there is not tertiary
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Simple SN2 reaction to prepare thiols
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What are disulfides
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Oxidation of thiols to give disulfides (1.proton transfer / 2.SN2 to make S-Br / 3.SN2 to give S-S
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Reduction of disulfides
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Sulfides?
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The sulfur analogs of ethers
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Explain different steps of oxidation of sulfides?
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Like Ether compounds they have two step of oxidation
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What is general structure of sulfoxides?
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What is the general structure of sulfones?
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First step of Oxidation of sulfide with NaIO4 to sulfoxides (does not go to suflones)
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Two moles of Hydrgenperoxide will oxidize sulfide to a sulfoxides and finally to sulfones
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What of the following is the correct drawing of sulfoxides (same for sulfones)?
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Both can be drawn. Because The S-O bonds in sulfoxides and sulfones actually have little double-bond character and consequently the orbital overlap of the P bond between these two atoms is not effective
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What is DMS? What is used for?
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DMS =dimethyl sulfide / It is the reducing agent in ozonolysis
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