CHEM1112 Lecture Notes - Lecture 2: Lone Pair, Electrophile, Nucleophile
16 May 2018
School
Department
Course
Professor
• Identify diastereomers as E or Z
E: same side, Z: different
• Identify electrophiles and nucleophiles in a reaction
Electron rich component (nucleophile). Donates lone pair, electron rich, arrow starts from the
nucleophile
Electron deficient component (electrophile). Seeks lone pair, electron deficient, arrow head (end) at the
electrophile.
• Follow a reaction mechanism using curly arrows
Curly arrows track movement of electron pairs in reaction. Arrow starts at source of electrons (lone pair
or bond), finishes where electrons end (bond or as a lone pair on an atom- used in Polar reactions. Polar
reactions always between nucleophile and electrophile.
An arrow from a bond= breaking of bond.
Alkene+ halogen> induced polarisation in the halogen molecule= polar charges + cause electrophile
formation (anything with delta + charge)
Arrow between two species= bond formed.
React twice- Br left over after 1 mol reacts >
Induces polarisation to product
Breaks carbocation to make final product.
find more resources at oneclass.com
find more resources at oneclass.com
Explaining acidity: difference in acidity - from resonance stabilisation of anion.
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Donates lone pair, electron rich, arrow starts from the nucleophile. Seeks lone pair, electron deficient, arrow head (end) at the electrophile. Curly arrows track movement of electron pairs in reaction. Arrow starts at source of electrons (lone pair or bond), finishes where electrons end (bond or as a lone pair on an atom- used in polar reactions. An arrow from a bond= breaking of bond. Alkene+ halogen> induced polarisation in the halogen molecule= polar charges + cause electrophile formation (anything with delta + charge) React twice- br left over after 1 mol reacts > Explaining acidity: difference in acidity - from resonance stabilisation of anion. Substitution on aromatic rings: electrophilic aromatic substitution- aromatic ring attacks electrophile with electron cloud, usually need catalyst to make electrophile more reactive. Addition (also halogenation): no water present, halogen polarised > halogen ion nucleophile electrons > electrophile carbon with double bond now broken > product. Replacing weak pi bond with stronger sigma bonds.
