Ch_322b_15.11

Ch_322b_15.11 - Chapter 15.11 lecture note

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
The Orientation of Electrophilic Aromatic Substitution Meta Substitution: When S is Electron-Withdrawing Meta substitution arises with substituents that are electron-withdrawing . When an electrophile adds meta to the substituent, the formed arenium ion has the most positive charge at positions ortho and para to the carbon of attachment. This distribution avoids placing additional positive charge on a ring carbon already electropositive because of S . CF 3 E + meta addition CF 3 + H E arenium ion CF 3 H E CF 3 H E + + CF 3 H E + CF 3 E + para addition CF 3 + H E arenium ion CF 3 H E + CF 3 H E + CF 3 H E + additional positive charge on electropositive carbon
Background image of page 1

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

View Full DocumentRight Arrow Icon
Ortho addition also leads to an arenium ion with additional positive charge on the electropositive carbon bonded to the trifluoromethyl group. CF 3 E + ortho addition CF 3 + H E arenium ion Based on the resonance structure descriptions of the distributions of the positive charge among the carbons centers, the stabilities of the arenium ions are: CF 3 + H E CF 3 + H E CF 3 + H E more stable less stable
Background image of page 2
Image of page 3
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 / 11

Ch_322b_15.11 - Chapter 15.11 lecture note

This preview shows document pages 1 - 3. Sign up to view the full document.

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