Highly Enantioselective Catalytic Lactonization at Nonactivated Primary and Secondary γ -C-H Bonds.

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.