Pd-catalyzed functionalization of alkenes and alkynes using removable tethers

Abstract

The palladium-catalyzed functionalization of alkenes is a versatile transformation in synthetic chemistry, but intermolecular processes often suffer from low reactivity and selectivity. Molecular tethers can be introduced to answer these challenges. They have been used successfully for decades, but their installation and removal normally required multi-step procedures. In this review, we will present progress in this area resulting in more efficient tethering processes. We will start with a brief overview of carbamate- and sulfone-based tethered functionalization of allylic alcohol and amine derivatives. Then the recent development of tethers that can be installed in situ on (homo)-allyl/propargyl amines or alcohols for double and triple bond functionalization will be described. The difunctionalization of alkenes and alkynes using trifluoro acetaldehyde based tethers developed by our group will be covered in more details. Finally, we will introduce the concept of tethers as catalytically formed chiral auxiliaries for asymmetric synthesis.