A rapid and diastereoselective method was developed for the [2,3]-sigmatropic rearrangement of N-allyl ammonium ylides, affording products in up to 95% isolated yields and up to 97:3 dr; most of the desired products were formed within 1 minute. For the asymmetric reaction, a chiral auxiliary was introduced to the starting compound, affording the rearrangement product with high diastereoselectivities.

A new chemoenzymatic one-pot strategy has been developed for the synthesis of α-hydroxy half-esters containing consecutive quaternary and tertiary stereocenters using asymmetric cascade catalysis. In this study, an asymmetric Ca 2+ -catalyzed [2,3]-Wittig rearrangement reaction was proven to be suitable for a combination with porcine liver esterase-mediated hydrolysis resulting in the enhanced enantiomeric purity of the obtained products in a one-pot synthesis compared to the stepwise method.