Access to Alkyl-Substituted Lactone via Photoredox-Catalyzed Alkylation/Lactonization of Unsaturated Carboxylic Acids

An efficient photoredox-catalyzed
alkylation/lactonization reaction
of unsaturated carboxylic acids by using alkyl N-hydroxyphthalimide
esters as alkylation reagents has been developed. Varieties of redox-active
esters derived from aliphatic carboxylic acids were proved viable
in this method, affording alkyl substituted lactones in moderate to
good yields. This redox-neutral procedure features mild conditions
and operational simplicity, which provides a new strategy for the
synthesis of alkyl substituted lactones.