A Continuous Homologation of Esters: An Efficient Telescoped Reduction–Olefination Sequence

Organic Letters 14(10), 2465-2467, DOI: 10.1021/ol300722e

A continuous protocol for the two-carbon homologation of esters to α,β-unsaturated esters is described. This multireactor homologation telescopes an ester reduction, phosphonate deprotonation, and Horner–Wadsworth–Emmons olefination, thus converting a three-operation procedure into a single, uninterrupted system that eliminates the need for isolation or purification of the aldehyde intermediates. The homologated products are obtained in high yield and selectivity.