What is horner-wadsworth-emmons?

Horner-Wadsworth-Emmons (HWE) reaction is a chemical reaction that involves the conversion of carboxylic acid derivatives to the corresponding alkenes. This reaction was developed by George W. Wadsworth, Andrew J. Pearson, and Ole J. Horner in late 1950s. HWE is a stereoselective and mild reaction used in organic synthesis.

The mechanism of HWE involves the formation of a ylide intermediate from the reaction of an alkyl phosphonate with a strong base such as sodium hydride, potassium tert-butoxide or sodium amide, and a carbonyl compound (aldehyde, ketone, or ester). This ylide intermediate then reacts with a second equivalent of the carbonyl compound to form the desired alkene product.

HWE reaction has found applications in the synthesis of a wide range of natural products, pharmaceuticals, and other organic molecules. It is often used as an alternative to the more harsh Wittig reaction, which requires the use of highly reactive and unstable reagents.

Overall, HWE reaction is a useful and versatile tool in organic synthesis, particularly for the preparation of complex polyene or polypropenoid structures with high stereochemical control.