Organic Chemistry Ch 17 – Flashcards
38 test answers
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What is OsO4 (osmium tetroxide) used for?
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It is used to convert alkenes into vicinal diols
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What reagent would you use to convert 1,2-ethanediol and bromoethane into 1,2-diethoxyethane?

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Sodium
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A dialkyl ether was allowed to react with excess hydrogen bromide, giving a mixture of bromocyclopentane and 1?bromobutane. Identify the ether.

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Butyl cyclopentyl ether
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When allowed to react with excess hydrogen bromide, an ether gave only one benzyl bromide. What was the ether?

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Dibenzyl ether
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When allowed to react with excess hydrogen bromide, an ether gave one mole of 1,5-dibromopentane per mole of ether. What was the ether?

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Oxane (aka tetrahydropyran, aka oxacyclohexane)
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Draw the reaction between Iodine ion and protonated tetrahydrofuran

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Iodine ion deprotonates the protonated tetrahydrofuran, causing the ring to open up
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Draw the reaction between the 4-iodobutanol and the new HI molecule

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Lone pair on the O attracts the hydrogen from the HI, I becomes an Ion once more
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Draw the reaction between the protonated 4-iodobutanol and the Iodine ion

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The protonated 4-iodobutanol now has water as a leaving group. Water boots off and the Iodine ion swoops in to takes its place, giving us 1,4-diiodobutane
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What product is synthesized from the reaction of tetrahydrofuran with HI and heat?

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1,4-diiodobutane
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What reagent reacts with propene to produce epoxypropane?

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CH3CO3H
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What reagent reacts with epoxypropane to produce a cyanoalcohol?

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1. NaCN, (DMSO ) or CH3S(O)CH3 2. H2O
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What reagent reacts with a cyanoalcohol to form 1-cyano-2-propanone?

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(Pyridinium chlorochromate) PCC, CH2Cl2
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What is the principal organic product formed in the reaction of ethylene oxide with sodium cyanide (NaCN) in aqueous ethanol?

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Anionic nucleophil NaCN opens the epoxide which is then protonated to form an alcohol
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What is the principal organic product formed in the reaction of ethylene oxide with phenyllithium (C6H5Li) in diethyl ether, followed by addition of dilute sulfuric acid?

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Phenyllithium provides a phenyl group as a nucleophil which attacks the epoxide, ethylene oxide, which opens the ring to form 2-phenylethanol
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What is the principal organic product formed in the reaction of ethylene oxide with sodium azide (NaN3) in aqueous ethanol

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Sodium azide provides azide as a nucleophile which attacks ethylene oxide and opens the ring to form 2-azidoethanol
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What reagent can convert cyclooctanol into cyclooctene?

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H2SO4 and heat cause dehydration of an alcohol to yield an alkene
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What reagent converts cyclooctene into cyclooctene oxide?

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CH3CO3H (peracid) convert alkenes into epoxides in one step
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What reagent converts cyclooctene oxide into trans-2-azidocyclooctanol?

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1. NaN3, DMSO 2. H2O Sodium azide (NaN3) in DMSO can open the epoxide to give a trans-configured alcohol after subsequent exposure to H2O
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Draw an azide (what is an azide?)

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Triple nitrogens bound together with double bonds
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Describe the reaction between an epoxide and sodium methoxide in methanol

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Sodium methoxide acts as a base. Nucleophilic attack to the epoxide at the least substituted position produces an Sn2 reaction to produce a vicinal diol where the epoxide was
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What reagent could you use to convert cyclohexanol to cyclohexanone?

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Na2Cr2O7, H2SO4, H2O Sodium dichromate in aqueous acid will convert secondary alcohols to ketones. Could also use PCC
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What reagent could you use to convert cyclohexanone to 1-methylcyclohexanol?

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1. Ch3MgBr, ether 2. Water Grignard rxn using methylmagnesium bromide will produce 1-methylcyclohexanol in one step
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What reagent could you use to convert 1-methylcyclohexanol to 1-methylcyclohexene?

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H2SO4 and heat Sulfuric acid and heat will cause dehydration of the alcohol to produce an alkene
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What reagent would you use to convert 1-methylcyclohexene to an epoxide?

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CH3CO3H Peracetic acid causes epoxide formation from alkenes
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If you wanted to make an epoxide from an alkene what reagent would you use?
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Peracetic acid (CH3CO3H)
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If you wanted to convert the epoxide into 2-ethoxy-2-methylcyclohexanol

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H2SO4(catalytic) and CH3CH2OH Ethanol and sulfuric acid will open the epoxide in a trans fashion, with ethanol bonding to the more highly substituted carbon of the epoxide
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What would you use to convert 2-pentyne to cis-2-pentene?

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H2, Lindlar catalyst
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What would you use to convert cis-2-pentene into a cis-epoxide?

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CH3CO3H peracetic acids form epoxides out of alkenes
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What would you use to convert a cis-epoxide into an (R,R)-2,3-pentanediol

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H2O, H2SO4 Aqueous acid will open the epoxide to form a vicinal diol in an anti fashion
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What does H2SO4 in methanol do to an epoxide?
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Opens it up
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What products are formed when you add bromocyclohexane and sodium 2-butanolate

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1. butan-2-ol 2. 1-cyclohexene 3. NaBr
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What happens when you combine iodoethane with sodium alkoxide?

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Sodium alkoxide acts as a nucelophile towards iodoethane to yield an alkyl ethyl ether
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What happens when you add LiAlH4, diethyl ether and water to 3,4-Epoxy-3-methyl-1-butene?

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Lithium aluminium hydride reduces epoxides to alcohols and hydride is transferred to the less substituted carbon of the epoxide ring. The alkene double bond stays put.
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What does LiAlH4 do to an epoxide?
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Reduces it to an alcohol
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