{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Lecture 4 - Aromatics

Lecture 4 - Aromatics - BME 201 Suggested problems review...

Info icon This preview shows pages 1–15. Sign up to view the full content.

View Full Document Right Arrow Icon
1 BME 201 Suggested problems review material: Vollhardt, 6 th Ed., Chapter 9, problems no. 56,57,58; new reactions and important concepts on page 374-377; reactions of alcohols on page 378, chapter 15, exercises 15-1, 15-2, 15-3, 15-4, “The big picture” on page 717 (aromaticity), selected “important concepts” on page 722. Todays lecture is based on Vollhardt, selected materials from chapter 9 ( ethers and thiols, alcohols ), chapter 15 ( aromatics ), chapter 22 ( phenols ) as well as materials mentioned on other selected handouts. Handouts may have marked chapter numbers and page numbers for suggested reading. You will find it easier to do the suggested problems and pass future quizzes and exams if you go over the reading prior to attempting to solve the suggested problems.
Image of page 1

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

View Full Document Right Arrow Icon
2 Sulfur Analogs of Alcohols and Ethers
Image of page 2
3 Sulfur Analogs of Alcohols and Ethers 9-10 The sulfur analogs of alcohols and ethers are thiols and sulfides. The IUPAC system calls the sulfur analogs of alcohols, R-SH, “thiols.” The –SH group in more complicated compounds is referred to as “mercapto.”
Image of page 3

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

View Full Document Right Arrow Icon
4 The sulfur analogs of ethers are called “sulfides” (common name, thioethers). The RS group is called “alkylthio,” and the RS - group is called “alkanethiolate.”
Image of page 4
5 Thiols are less hydrogen-bonded and more acidic than alcohols. Compared to oxygen, sulfur has a large size, diffuse orbitals and a relatively nonpolarized S-H bond. The boiling points of thiols are similar to those of the analogous haloalkanes.
Image of page 5

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

View Full Document Right Arrow Icon
6 Thiols are more acidic than water and can therefore be easily deprotonated by hydroxide and alkoxide ions:
Image of page 6
7 Thiols and sulfides react much like alcohols and ethers. The sulfur in thiols and sulfides is more nucleophilic than the oxygen in the analogous compounds . Thiols and sulfides are readily made through nucleophilic attack by RS - or HS - on haloalkanes:
Image of page 7

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

View Full Document Right Arrow Icon
8 Sulfides are prepared by the alkylation of thiols in the presence of a base, such as hydroxide. The nucleophilicity of the generated thiolates is much greater than that of hydroxide which eliminates the competing S N 2 substitution by hydroxide ion.
Image of page 8
9 Sulfides can attack haloalkanes to form sulfonium ions. Sulfonium ions are subject to nucleophilic attack, the leaving group being a sulfide.
Image of page 9

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