Biocatalysts for cascade reaction: porcine pancreas lipase (PPL)-catalyzed synthesis of bis(indolyl)alkanes

A cascade reaction between aldehydes and indole catalyzed by lipase from porcine pancreas Type II (PPL) in solvent mixture at 50 A degrees C was reported for the first time. Some control experiments had been designed to demonstrate that the PPL was responsible for the cascade reaction. After the optimization of the stepwise process, a series of bis(indolyl)alkanes were prepared in moderate to excellent yields under the catalysis of PPL.