TL;DR: In this paper, a review of recent developments in the field of redox-active ester (RAE)-based cross-couplings since the initial discovery has been presented.
Abstract: Recent years have witnessed a resurgence of novel, efficient and practical protocols for radical-mediated cross-coupling reactions involving N-(acyloxy)phthalimides (NHPI esters) as redox-active esters. After the initial discovery of the redox-active properties of NHPI esters, exciting examples of SET-based cross-coupling reactions under thermal or photolytic conditions leading to diverse C–X (X=C, B, Si, Se, S) bonds have been published. The operational simplicity and broad applicability exhibited in redox-active NHPI ester-based cross-couplings bode well for their widespread adoption. The review presented herein covers all the recent developments in the field of redox-active ester (RAE)-based cross-couplings since the initial discovery. Depending on the conditions employed the reactions have been categorized into photoinduced and non-photoinduced cross-couplings with representative examples and insightful mechanistic discussions.
TL;DR: The Gabriel synthesis of primary amines as discussed by the authors is based on a combination of N-substituted phthalimides with halogenoalkanes and with a variety of other alkylating agents.
Abstract: Reaction of potassium phthalimide with halogenoalkanes and with a variety of other alkylating agents leads to the N-alkylphthalimide. N-Substituted phthalimides may be converted into the corresponding primary amine by hydrolysis or hydrazinolysis. The scope and limitations of these reactions, which together constitute the Gabriel Synthesis of primary amines, are reviewed.
TL;DR: 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 fractions as discussed by the authors.
Abstract: 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 fra...
TL;DR: Deuterium labeling and competition experiments reveal that the reductive radical coupling of tertiary N-(acyloxy)phthalimides with electron-deficient alkenes can be terminated by both hydrogen-atom transfer and single-electron reduction followed by protonation, and that this mechanistic duality is controlled by the presence or absence of i-Pr2NEt.
Abstract: Tertiary carbon radicals have notable utility for uniting complex carbon fragments with concomitant formation of new quaternary carbons. This article explores the scope, limitations, and certain mechanistic aspects of Okada’s method for forming tertiary carbon radicals from N-(acyloxy)phthalimides by visible-light photocatalysis. Optimized conditions for generating tertiary radicals from N-(acyloxy)phthalimide derivatives of tertiary carboxylic acids by visible-light irradiation in the presence of 1 mol % of commercially available Ru(bpy)3(PF6)2, diethyl 1,4-dihydro-2,6-dimethylpyridine-3,5-dicarboxylate (8), and i-Pr2NEt and their coupling in dichloromethane at room temperature with alkene acceptors were developed. Four representative tertiary N-(acyloxy)phthalimides and 15 alkene radical acceptors were examined. Both reductive couplings with electron-deficient alkenes and radical substitution reactions with allylic and vinylic bromides and chlorides were examined with many such reactions occurring in go...