13 Feb 2019
School
Department
Course
Organic Reactions (Lec 17)
Nucleophile
- Electron-rich
- Donor of electron pair (Lewis base) → lone pair or pi-bond
- Neutral or negatively charged
Electrophile
- Electron-poor
- Acceptor of electron pair (Lewis acid) → polarized bond or empty orbital
- Neutral or positively charged
*Electron-rich nucleophiles use their electron pair to “attack” electron-deficient
electrophiles
- Electrons always move from nucleophile to electrophile
- Electron pair used to establish bond to electrophile
- Flow of electrons follows the polarization of the bond in the electrophile
- Bond making and breaking are FREQUENTLY simultaneous
Electrophilic addition of HX to an alkene to form a haloalkane
- Ether is the reaction solvent → the medium in which the reaction takes place
- Reaction mechanism → sequence of elementary (simple) steps (ie. simple bond
breaking/forming reactions) → CENTRAL to the understanding of organic chemistry
- Reaction mechanism shown above → two elementary steps involving one intermediate