User:Benjah-bmm27/degree/1/VKA

Introduction
"Reactions and Synthesis with Carbonyl Compounds", Professor Varinder Aggarwal.

General features of carbonyl reactions

 * The carbonyl group is electrophilic at carbon, so many nucleophiles can (and do) attack there
 * The mechanisms of these reactions generally involve the following steps:
 * A nucleophile adds to the carbon atom of a carbonyl group. This step is called nucleophilic addition.
 * The product formed by nucleophilic addition to a carbonyl group is generally a tetrahedral carbonyl addition compound.
 * If the tetrahedral product is unstable, it can collapse back to a trigonal carbonyl compound by expelling a leaving group.
 * The overall process of nucleophilic addition followed by leaving group elimination is called nucleophilic acyl substitution, because the nucleophile replaces the leaving group as a substituent on the carbonyl carbon.

Particular examples of carbonyl reactions

 * Reduction of aldehydes and ketones to alcohols with sodium borohydride, NaBH4
 * Reduction of esters to alcohols with lithium aluminium hydride, LiAlH4
 * Jones oxidation: oxidation of primary alcohols to carboxylic acids and secondary alcohols to ketones with chromium trioxide, CrO3 (can also use e.g. pyridinium chlorochromate, PCC)
 * Ester hydrolysis, such as saponification
 * Alkylimino-de-oxo-bisubstitution
 * RCO2H + OSCl2 → RCOCl + HCl + SO2
 * goes via an SNi mechanism