A protocol for the photooxidative activation of α-silylamines and α-amino acids for desilylative and decarboxylative additions, allylations and heteroarylations in the presence of graphitic carbon nitride (g-C 3 N 4) was developed. The procedure has broad scope and provides the desired products in high yields. The heterogeneous nature of the g-C 3 N 4 catalytic system enables easy recovery and recycling as well as the use in multiple runs without loss of activity. The photoredox catalyzed reactions can also be conducted in continuous photo flow fashion and scaled up to gram-scale. Thus, the stable and readily available polymeric g-C 3 N 4 provides an alternative to homogeneous photosensitizers for the generation of valuable radical intermediates for applications in synthesis and catalysis.

An efficient synthetic procedure for the preparation of fused 2,3-dihydrofuran derivatives was developed with the assistance of pyridinium ylide. A sequential one-pot, two-step tandem reaction starting from pyridine, aromatic aldehyde, dimedone, or 4-hydroxycoumarin and alpha-phenacyl bromide or p-nitrobenzyl bromide with triethylamine as catalyst proceeded smoothly in acetonitrile. (1)H NMR spectroscopy and single-crystal analysis demonstrated that the obtained 2,3-dihydrofurans are trans isomers.

A mild approach for the decarboxylative aminomethylation of aryl sulfonates by the combination of photoredox and nickel catalysis through C-O bond cleavage is described for the first time. A wide range of aryl triflates as well as aryl mesylates, tosylates and alkenyl triflates afford the corresponding products in good to excellent yields.

A new oxidative [3 + 2] cycloaddition of N-substituted hydroxylamines with alkenes was established under visible light photoredox catalysis. This novel protocol provides a rapid, mild, and efficient access to valuable five-membered ring isoxazolidine heterocycles in a concise fashion.

Described herein is a visible-light mediated intermolecular radical cyclization approach to access heterocycles. Heteroatom radicals, such as silicon and phosphorus atom radicals, were generated via direct hydrogen atom abstraction by the photoexcited catalyst species with hydro-silanes and phosphine oxides. The radical addition/cyclization/ HAT (hydrogen atom transfer) reaction sequences of 1,6-enynes and 1,6-dienes were highly efficient delivering the desired heterocycles in good yields.H eterocyclic scaffolds are ubiquitous in natural products and exhibit a broad range of pharmacological properties, which attracted great attention for the drug discovery and as building blocks for the synthesis of pharmaceutically relevant compounds and other highly functionalized molecules. 1 The intermolecular radical addition/cyclization cascade presents a powerful and efficient synthetic strategy to access complex organic heterocycles. 2,3 Among the various element radicals, heteroatom radicals, such as silicon and phosphorus atom radicals, recently have drawn great attention in the organic transformation. 4,5 Specifically, visible-light photocatalysis has demonstrated to be a powerful modus for radical generation. 6 Although there are a number of reports on visiblelight mediated radical addition across the π-system, few radical cyclization reactions have been reported. 7,8 However, most of the radicals were generated by a single-electron transfer process, or assisted by a hydrogen atom transfer cocatalyst. 9 Recently, the group of Wu demonstrated that the photoexcitation of Eosin Y could act as a hydrogen atom transfer (HAT) catalyst, where the HAT with oxygen adjacent to a C− H bond or aldehydes generated the carbon radicals. 10,11 The silicon and phosphorus atom radical formation via a hydrogen atom abstraction from hydro-silanes and phosphine oxides are well-known. 12−15 To the best of our knowledge, use of a visible-light excited catalyst for direct silicon and phosphorus atom radical generation is rare.Given the similar bond dissociation energies (BDEs) of the Si−H of 1,1,1,3,3,3-hexamethyl-2-(trimethylsilyl)trisilane (BDE = 79 kcal/mol) and P−H bond of phosphine oxide (BDE ≈ 85 kcal/mol) with C−H (BDE ≈ 90 kcal/mol), 16 both hydrosilylative and hydrophosphorylative cyclizations of enynes under visible-light photo-HAT catalysis were evaluated.The visible light irradiation of the organic dyes, such as Eosin Y, could generate the photoexcited catalyst species Eosin Y* (Scheme 1). 10 The hydrogen atom abstraction of Eosin Y* with hydro-silanes or phosphine oxides (FG-H) would give the silicon or phosphorus atom radicals (FG• radical), leading the formation of Eosin Y−H, the radical addition of FG• across the CC π-bond of the 1,6-enyne which would give the vinyl radical intermediate I-1; the 5-exo radical cyclization of the