Natural Sunlight Photocatalytic Synthesis of Benzoxazole-Bridged Covalent Organic Framework for Photocatalysis.

Although natural sunlight-mediated photocatalysis is a clean, efficient, and green approach to access organic products, its application in the synthesis of covalent organic frameworks (COFs), however, is still unprecedented. Herein, we first report the sunlight photocatalytic synthesis of COF under ambient conditions. Furthermore, this "window ledge" reaction generated benzoxazole-linked COF is stable and can be applied as a reusable photocatalyst to highly promote visible-light-driven aerobic oxidation of sulfides to sulfoxides. These results not only enrich the COF synthetic methodology but also open a new route to access COFs in a green and sustainable way.

Gold-Catalyzed Divergent Ring-Opening Rearrangement of Cyclopropenes Enabled by Dichotomous Gold-Carbenes.

The gold-catalyzed ring-opening rearrangement of cyclopropenes affords an efficient route to either polysubstituted naphthols or aryl-substituted furans. Owing to the unique dichotomy of gold-carbenes, this protocol provides a switchable reaction selectivity between naphthols and furans enabled by the use of TFP-Au(MeCN)SbF6 (tri(2-furyl) phosphine) or PNP(AuNTf2 )2 (bis(diphenylphosphino)(isopropyl) amine) as catalysts respectively. It is proposed that the gold-carbene intermediate might be involved in the cyclopropene→naphthol rearrangement while the gold-carbocation is more likely to be involved in the cyclopropene→furan rearrangement.

Decarboxylative tandem C-N coupling with nitroarenes via SH2 mechanism.

Aromatic tertiary amines are one of the most important classes of organic compounds in organic chemistry and drug discovery. It is difficult to efficiently construct tertiary amines from primary amines via classical nucleophilic substitution due to consecutive overalkylation. In this paper, we have developed a radical tandem C-N coupling strategy to efficiently construct aromatic tertiary amines from commercially available carboxylic acids and nitroarenes. A variety of aromatic tertiary amines can be furnished in good yields (up to 98%) with excellent functional group compatibility under mild reaction conditions. The use of two different carboxylic acids also allows for the concise synthesis of nonsymmetric aromatic tertiary amines in satisfactory yields. Mechanistic studies suggest the intermediacy of the arylamine-(TPP)Fe(III) species and might provide a possible evidence for an SH2 (bimolecular homolytic substitution) pathway in the critical C-N bond formation step.