Ethers Nanoplasmonic Research Group Organic Chemistry Chapter 8 Part I

Ethers and Epoxides (What ?) Ethers: Compounds that have two organic groups connected to a single oxygen atom Epoxides: Cyclic three-membered ring ethers

Ethers (how to name ?) Trivial name: Describing two alkyl groups and appending “ether” 2-methoxypentanetrans-2-methoxycyclohexanol1,3,5-trimethoxybenzene IUPAC system: the general formula “alkoxyalkane” ethyl methyl ether diethyl ether (the prefix dis-is sometimes omitted) diphenyl ether

Ethers (physical properties) A relatively low boiling point: compared to that of the analogous alcohols: No hydrogen bonds amongst each other (page 236) Water-soluble: two lone pairs of electrons on the oxygen atoms makes hydrogen bonding with water molecule possible (page 237) Lewis bases: can coordinate to magnesium in Grignard reagents and boron compounds

One quick question!! If you are given to synthesize C-C bond, then how to make it ? There are two options C C- C+ Free radical reaction We all know how to generate carbocation, but what about C-???

The Grignard Reagent (I) Nucleophilic carbon!!!!: carbanion Organometallic chemical reaction in which alkyl- or aryl- magnesium halides (Grignard reagents), act as nucleophiles, attack electrophilic carbon atoms that are present within polar bonds (e.g., carbonyl group)

The Grignard Reagent (II) Important tool in the formation of carbon- carbon bonds, carbon-silicon, carbon- boron, and other carbon-heteroatom bonds The addition of the GR reagent to the carbonyl typically proceeds through a six- membered ring transition state

Ethers in the GR (solvent!!) Acting as a Lewis base, ether stabilizes a Grignard reagent Carbanions are strong bases: Thus, most Grignard reactions occur in solvents such as anhydrous diethyl ether or THF

Preparation of Ethers Intermolecular Dehydration of Alcohols: Effective for making symmetric ethers, why? Nucleophilic Displacement of Alkyl Halides by Alkoxide (Williamson ether synthesis: treatment of alcohols with strong bases!!!) Electrophilic Addition of Alcohols to Alkenes