CH 221 1st Edition Lecture 28Outline of Last Lecture I. Halide ReactionsOutline of Current Lecture II. AlcoholsIII. Oxidation of AlcoholsIV. EthersCurrent LectureII. Alcohols are readily available but unreactive- Alkyl halides are less available but more reactive and can be used to synthesize lots of compounds- Converting alkyl halides into alcohols require the presence of pyridine- Can form compounds such as phosphorus tribromide and thionyl chloride- Pyridine is a solvent that acts as a base- The dehydration of is an elimination reaction and is also reversible- To prevent alkenes from adding water and reforming the alcohol, the water is removed as it is formed - The dehydration of secondary and tertiary alcohols are E1 reactions- Dehydration is also a regioselective reaction (major product is more stable alkene)- Tertiary alcohols are the easiest to dehydrate, the rate of dehydration reflects the ease of carbocation formation- An E1 reactions creates a carbocation intermediate so be watchful for carbocation rearrangement- Dehydration of a primary alcohol is an E2 reaction in which both E2 and Sn2 products are obtained- Dehydration is stereoselective- Major product is stereoisomer with the largest groups on opposite sides of the double bondIII. Oxidation of Alcohols- Involves the presence of chronic acid- Tertiary alcohols can not be oxidized into a carbonyl compoundThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- Alcohols and ethers have similar leaving groups- They both have to be activated before compounds can reactIV. Ether can be activated by protonation- If a relatively stable carbocation is formed when ROH leaves, it will be a Sn1 reaction- Ether undergoes Sn1 reactions unless they would form a primary carbocation- Ethers are commonly used as solvents because they react only with hydrogen
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