A Cu-catalyzed selective aerobic heterocoupling of terminal alkynes is disclosed, which enables the synthesis of a broad range of unsymmetrical 1,3-diynes in good to excellent yields. The results disprove the long-held belief that homocouplings are exclusively favored in the Glaser-Hay reaction.

Functional group substituted 1-naphthylamines, especially N-methylated ones, play important roles in numerous chemical and biological processes. However, these compounds' general and stepeconomic syntheses are highly limited, which seriously restricts efforts to improve the properties and develop new functions for this kind of compound. In this report, we describe the development of an efficient, convenient, and general method for the synthesis of valuable functionalized 1-naphthylamines directly from readily available terminal alkynes, 2-bromoaryl ketones, and amides via Cu(I)-catalyzed benzannulation in a green solvent (i.e., water) under Pd-and ligand-free conditions. A total of 82 functionalized 1naphthylamines, especially synthetically and biologically useful N-methylated compounds, are synthesized in isolated yields up to 95%. Some unique features of the reaction are as follows: (1) exclusive 6-endo-dig selectivity, (2) ready incorporation of a broad range of functional groups directly from easily available substrates, and (3) amides that can be used as aminating agents and that are excellent alternatives to toxic and/or odorous amines. Due to facile tuning of functional groups for the reaction, the products possess good electronic donor−acceptor structures and exhibit intriguing photophysical properties, such as tunable and polarity-sensitive fluorescence emission and large Stokes shifts (up to 258 nm). Utilizing the products' unique polaritysensitive fluorescence response, we successfully applied the 1-naphthylamine derivatives, such as compound 91, to image lipid droplets (LDs) and monitor cellular LDs growth. The previously mentioned advantages of this methodology, along with the mild conditions, simple operation, and scalable synthesis, may allow this novel reaction to be extended to varied applications in chemistry, biology, and materials science.

With sunlight or blue LEDs irradiation, regioselective decarboxylative alkylation of various non-aromatic heterocycles has been realized via C (sp 3 )-centered radical C(sp 2 )À C(sp 3 ) bond formation under oxidant-free conditions at room temperature. This reaction readily incorporates various functional alkyl groups into heterocyclic compounds without observation of any alkyl radical rearrangement and represents a mild and general tool for the preparation of valuable alkyl group-functionalized heterocyclic compounds.

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A facile, general, and economical synthesis of diversely functionalized pyrimidines has been realized under basic conditions via the copper-catalyzed cyclization of ketones with nitriles. The reaction proceeds via a novel pathway involving the nitriles acting as electrophiles and consecutive C-C bond and two C-N bond formations and shows broad substrate scope and good tolerance of many important functional groups. This strategy represents a new platform for constructing pyrimidine structures.