The past decade has witnessed the emergence of N-(acyloxy)phthalimides (NHPI esters) and its derivatives at the forefront of synthetic methods facilitating the construction of diverse molecular frameworks from the readily available carboxylic acid feedstock. The NHPI esters are predisposed to undergo reductive fragmentation via a single electron transfer (SET) process under thermal, photochemical, or electrochemical conditions to generate the corresponding carbon-or nitrogencentered radicals that participate in a multitude of synthetic transformations to forge carbon−carbon and carbon−heteroatom bonds. The chemistry involving NHPI esters has received broad applicability not only in well-designed cascade annulations but also in medicinal chemistry and natural product synthesis. This comprehensive Review, broadly categorized according to the nature of the bond formation, details the progress made in this field since the initial discovery by providing representative examples with mechanistic details, with an emphasis on challenges and future directions.

A transition-metal-free one-pot three-component annulation between diaryliodonium triflates, cyclic and acyclic aliphatic amines, and carbon disulfide providing a convenient and efficient access to biologically relevant S-aryl dithiocarbamates is developed. The reaction does not require metal, base, or any other additive and operates under mild and ambient conditions. This methodology is robust, scalable, and exhibits a broad substrate scope. The in silico analysis revealed that the majority of the compounds have a drug-likeness and good ADMET characteristics.

An organophotoredox-catalyzed reduction/addition/oxidation cascade of N-protected maleimides and N-(acyloxy)phthalimides is documented. The mild and efficient redox-neutral process involves hitherto unknown Giese-type addition of aryloxy-alkyl radicals on the N-protected maleimides and...

Synthetic methods enabling late-stage modification of heterocycles hold tremendous importance in the pharmaceutical and agrochemical industry and drug discovery. Accordingly, efficient, functional group tolerant and selective late-stage alkylation of valuable molecular entities is of enormous significance and well-acknowledged in medicinal chemistry. Radical alkylation of heteroarenes employing carboxylic acids as the alkyl radical precursor represents one of the most direct ways of CÀ H functionalizations of heterocycles. Recently, the field has undergone a revolutionary development especially with regard to the generation of alkyl radicals under much milder conditions. In this regard N-(acyloxy)phthalimides (NHPI esters) have emerged as a suitable precursor of a diverse set of alkyl radicals allowing formal CÀ H alkylation of not only N-heteroarenes but a diverse set of non-aromatic heterocycles under visible light photocatalysis or electrochemical conditions. This review delineates all these discoveries and provides readers a comprehensive overview of this rapidly expanding field.

An organophotoredox catalyzed efficient and robust approach for the synthesis of highly important 3‐alkyl substituted chroman‐4‐one scaffold is developed using visible light induced radical cascade cyclization strategy. The reaction is initiated through the generation of alkyl radicals from N‐(acyloxy)phthalimides under photoredox conditions, which subsequently undergo intermolecular cascade radical cyclization on 2‐(allyloxy)arylaldehydes to afford chroman‐4‐one scaffolds. The presented strategy is attractive with regard to mild reaction conditions, operational simplicity, high functional group tolerance and broad substrate scope.