Novel densely functionalized β2,2-amino acids were obtained in almost enantiopure form using down to 20 ppm of a chiral phase-transfer catalyst.

Novel α-trifluoromethylthiolated-β2,2-amino acids were obtained in high enantiopurities under chiral phase-transfer catalysis.

A novel high yielding, enantio- and diastereoselective protocol for the synthesis of α-allylated highly functionalised β-amino acid derivatives by adding isoxazolidin-5-ones to MBH carbonates under asymmetric phase-transfer catalysis has been developed.

We herein report the ammonium saltcatalyzed synthesis of chiral 3,3-disubstituted isoindolinones bearing a heteroatom functionality in the 3-position. A broad variety of differently substituted CF 3 Sand RS-derivatives were obtained with often high enantioselectivities when using Maruoka's bifunctional chiral ammonium salt catalyst. In addition, a first proof-of-concept for the racemic synthesis of the analogous F-containing products was obtained as well, giving access to one of the rare examples of a fairly stable α-F-α-amino acid derivative.

The enantioselective synthesis of a broad variety of novel differently functionalized α-halogenated α-aryl-β 2,2 -amino acid derivatives by means of an ammonium-salt-catalyzed asymmetric α-halogenation of isoxazolidin-5-ones was accomplished. Key to success to obtain high levels of enantioselectivities was the use of Maruoka’s spirocyclic binaphthyl-based ammonium salts, and detailed accompanying mechanistic studies using density functional theory methods revealed the key features for the catalyst–substrate interactions.