Copper‐Catalyzed Bis‐ or Trifunctionalization of Alkynyl Carboxylic Acids: An Efficient Route to Bis‐ and Tris‐selenide Alkenes

One-Pot Synthesis of 3-Methyl-2-arylimidazo[1,2-a]pyridines Using Calcium Carbide as an Alkyne Source

An efficient method for the construction of 3-methyl-2-arylimidazo[1,2-a]pyridines from the reactions of calcium carbide, 2-aminopyridines, and aromatic aldehydes is described. The notable advantages for this strategy include the use of an inexpensive and concise solid alkyne source, cheap and readily available raw materials, wide-scope substrates, and a simple work-up procedure.

Decarboxylative Oxyacyloxylation of Propiolic Acids: Construction of Alkynyl-Containing α-Acyloxy Ketones

Novel decarboxylative oxyacyloxylation of propiolic acids has been developed. This reaction provides an efficient access to alkynyl-containing α-acyloxy ketones from readily available starting materials and exhibits significant functional group tolerance. Furthermore, oxyacyloxylation of terminal alkynes and aliphatic propiolic acids was also developed. A possible reaction mechanism is proposed based on mechanistic studies.

Light-mediated Seleno-Functionalization of Organic Molecules: Recent Advances

Organoselenium compounds constitute an important class of substances with applications in the biological, medicinal and material sciences as well as in modern organic synthesis, attracting considerable attention from the scientific community. Therefore, the construction of the C-Se bond via facile, efficient and sustainable strategies to access complex scaffolds from simple substrates are an appealing and hot topic. Visible light can be regarded as an alternative source of energy and is associated with environmentally-friendly processes. Recently, the use of visible-light mediated seleno-functionalization has emerged as an ideal and powerful route to obtain high-value selenylated products, with diminished cost and waste. This approach, involving photo-excited substrates/catalyst and single-electron transfer (SET) between substrates in the presence of visible light has been successfully used in the versatile and direct insertion of organoselenium moieties in activated and unactivated C(sp³ )-H, C(sp² )-H, C(sp)-H bonds as well as C-heteroatom bonds. In most cases, ease of operation and accessibility of the light source (LEDs or commercial CFL bulbs) makes this approach more attractive and sustainable than the traditional strategies.

Visible-Light-Promoted Selenylative Spirocyclization of Indolyl-ynones toward the Formation of 3-Selenospiroindolenine Anticancer Agents

A metal-free and efficient visible-light-induced spirocyclization of indolyl-ynones with diselenides at room temperature under air atmosphere to prepare 3-selenospiroindolenines in moderate to good yields has been developed. The resulting products were tested for in vitro anticancer activity by MTT assay, and compounds 3 c and 3 e showed potent cancer cell-growth inhibition activities.

Chelation-assisted transition metal-catalysed C–H chalcogenylations

This review summarizes recent advances in C–S and C–Se formationsviatransition metal-catalyzed C–H functionalization utilizing directing groups to control the site-selectivity.

Trifunctionalization of alkenes and alkynes

In this review, the development of trifunctionalization methods for alkenes and alkynes, including arynes and allenes, over the last decade is disclosed.

Copper-Catalyzed Trifunctionalization of Alkynes: Rapid Formation of Oxindoles Bearing Geminal Diboronates

A copper-catalyzed trifunctionalization of alkynes that provides rapid access to oxindoles bearing a geminal diboronate side chain, highlighted by the simultaneous formation of one C-C bond and two C-B bonds, is reported. This new reaction features simple reaction conditions (ligand-free catalysis), a general substrate scope, and excellent chemoselectivity. Mechanistic study revealed a reaction sequence constituted by, in the order, borylation, intramolecular cross-coupling, hydroboration, which has been rarely documented.