Phosphorus Reagents for Two‐, Three‐, and Four‐Carbon Homologation of Carbonyl Compounds to Functionalized Olefins

This chapter highlights the most popular methods employed for the two‐carbon homologation of aldehydes and ketones and shorter sections on three‐ and four‐carbon homologation reactions defining the limit of carbonyl‐, or equivalent, directed homologation reactions. Methods for the conversion of carbonyl compounds to extended carbonyls, stereochemically defined unsaturated esters, alkenals, enones, and vinyl ethers are described. Representative applications toward the total synthesis of natural products and chemical biology investigations are presented to highlight the fundamental status occupied by homologation processes in organic synthesis.