Oxygen attacks P, 1 Br leaves. Final product Br on Carbon and OHPBr2.
Mechanism of Thionyl Chloride Reaction
1. Thiony Chloride + R-OH (back side attack)
2. Double bond forms between Cl--S, double bond forms with O--S
3. Cl-attacks thionyl chloride H proton to form chlorosulfite ester + HCl
4. R group removed and O–S bond forms a double bond- Product 1: SO2
5. R group bonds to Cl to form R–Cl Product 2: R–Cl
Formation of sulfonates
nucleophilic substitution, alcohol is nucleophile
not inverted like normal SN2
sulfonate ions are weak bases and excellent leaving groups
alcohol attacks the Sulfur and halide breaks off
acid-catalyzed dehydration of alcohols
alcohol -> alkene + H2O
3˚ easiest to dehydrate
2, 1 require strong acid and high heat + rearrangement
start with alkene, end with a ketone. breaking of C=C and forming C=O signifies pinacol rearrangement; rearrangement occurs to give MORE stable carbocation (ketone forms at less stable carbon)
Oxidation of Alcohols
Primary alcohols can be oxidized to aldehydes using PCC and further oxidized to carboxylic acids using KMnO4, Na2Cr2O7, or CrO3. Secondary alcohols can be oxidized to ketones using any of these oxidants.
1° OH → aldehyde→ carboxylic acid
2° OH → ketone
3° OH → doesn't react
O3, Cr2O7, CrO4, KMnO, Jones, Collins, PCC...
Acids used in alcohol Oxidation
-Chromic Acid (H2CrO4).
-Pyridinium Chlorochromate (PCC).
-Periodic Acid Oxidation of Glycols.
Anhydrous, non-acidic conditions
1° alcohol: Stops at an aldehyde. 2° alcohol: Gives a ketone
Oxidation: conversion of primary alcohols to aldehydes and secondary alcohols to ketones
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