Highly Enantioselective Catalytic Lactonization at Nonactivated Primary and Secondary <i>γ</i>-C–H Bonds
Arnau Call, Giorgio Capocasa, Andrea Palone, Laia Vicens, Eric Aparicio, Najoua Choukairi Afailal, Nikos Siakavaras, Maria Eugènia López Saló, Massimo Bietti, Miguel Costas
Abstract
High Resolution Image Download MS PowerPoint Slide Chiral oxygenated aliphatic moieties are recurrent in biological and pharmaceutically relevant molecules and constitute one of the most versatile types of functionalities for further elaboration. Herein we report a protocol for straightforward and general access to chiral γ -lactones via enantioselective oxidation of strong nonactivated primary and secondary C( sp 3 )–H bonds in readily available carboxylic acids. The key enabling aspect is the use of robust sterically encumbered manganese catalysts that provide outstanding enantioselectivities (up to >99.9%) and yields (up to 96%) employing hydrogen peroxide as the oxidant. The resulting γ -lactones are of immediate interest for the preparation of inter alia natural products and recyclable polymeric materials.