Recent advances in the Willgerodt-Kindler reaction.

The Willgerodt-Kindler reaction has, in recent years, received limited attention and application in synthetic organic chemistry. With the advent of new technology such as microwave-assisted heating, several new, high-yielding, practical, and more environmentally friendly reaction protocols have been developed. This review aims to once again draw attention to this relatively underutilised process by highlighting the recent developments in the Willgerodt-Kindler reaction in the synthesis of (thio)amides, carboxylic acids, and heterocycles.