Ch_322b_21.03

Ch_322b_21.03 - Chapter 21.3 lecture note

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Reactions of Phenols Acylation of the Hydroxyl Group Acylation is the introduction of the acyl group, RC - O = . The hydroxyl group in phenols may be acylated by either of two general procedures: OH + RCOCR O acid anhydride base O CR + RCOH OH + RCCl base acyl chloride O CR + HCl O O O O O
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Phenols in the Williamson Synthesis of Ethers Because of their acidity (pK a ~10), phenols are easily converted into their phenoxide ions with sodium or potassium hydroxide. The nucleophilic phenoxide ions react with alkyl halides (or equivalent compounds) by an S N 2 mechanism to yield aryl alkyl ethers . ArOH HO - ArO - phenoxide ion RX (where X = Cl, Br, I or OSO 2 R or OSO 2 OR) ArOR via Ar-O: : - R X: All the usual structural limitations of the S N 2 mechanism apply. Examples OH Br p-bromophenol NaOH O - Na + Br sodium p-bromophenoxide CH 3 I OCH 3 Br + NaI p-bromoanisole CH 3 OSOCH 3 O = O (dimethyl sulfate) OCH 3 Br p-bromoanisole Na + - OSOCH 3 O O +
Background image of page 2
Cleavage of Aryl Alkyl Ethers Reaction with HI or HBr cleaves these ethers in a specific direction:
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 10/20/2009 for the course CHEM 322BL at USC.

Page1 / 9

Ch_322b_21.03 - Chapter 21.3 lecture note

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online