Overman Rearrangement

In 1974, the American chemist Larry Overman reported the thermal and mercuric ion catalyzed rearrangement of allylic trichloroacetimidates to create the corresponding trichloroacetamides. Subsequently the 1,3-transposition of alcohol and amine functionalities via [3,3]-sigmatropic rearrangement of allylic trichloroacetimidates became known as the Overman rearrangement. The allylic trichloroacetimidates are readily prepared by treating the corresponding alcohols with trichloroacetonitrile in the presence of catalytic amounts of a base, or DBU.

In recent decades, the Overman rearrangement has become an important carbon-nitrogen bond-forming reaction used in many synthesis campaigns. For example, during the total synthesis of sphingofungin E by N. Chida and colleagues, the stereocenter at C5 was formed using the Overman rearrangement of an allylic trichloroacetimidate derived from diacetone-D-glucose.