Weigao Hu

Transition-metal-free synthesis of vinyl sulfones via tandem cross-decarboxylative/coupling reactions of sodium sulfinates and cinnamic acids

A transition-metal-free synthesis of vinyl sulfones, utilizing sodium sulfinates and cinnamic acids through tandem cross-decarboxylative/coupling reactions, has been developed. This transformation is simple, efficient and environmentally benign, with a wide range of substrate scope and exceptional functional group tolerance.

Csp3–P versus Csp2–P Bond Formation: Catalyst-Controlled Highly Regioselective Tandem Reaction of Ene-Yne-Ketones with H-Phosphonates

Under copper-catalyzed or base-promoted conditions, a wide range of ene-yne-ketones react with H-phosphonates to afford various phosphorylated furans in good yields. A copper carbene generation or a Michael addition is proposed as the key step in the selective construction of the Csp(3)-P or Csp(2)-P bond, which is supported by carbene capture reactions and interval (31)P NMR experiments. Furthermore, this method features inexpensive metal catalysts, no usage of oxidant, and high atom economy, which make it attractive and practical.

Palladium-Catalyzed Redox-Neutral N-O/C(sp3)-H Functionalization of Aryl Oximes with Isocyanides

A redox-neutral palladium-catalyzed N-O/C(sp3)-H functionalization of aryl oximes with isocyanides has been developed. Various pyrrole derivatives were prepared in good to excellent yields through oxime carbamate as a key intermediate and internal oxidant in this process. Furthermore, this transformation also features readily available starting materials, good functional group tolerance, and excellent regioselectivity.

Palladium-catalyzed cascade reaction of haloalkynes with unactivated alkenes for assembly of functionalized oxetanes

A novel and efficient palladium-catalyzed aerobic cascade reaction of haloalkynes with unactivated alkenes for synthesis of functionalized oxetanes has been demonstrated. This cascade protocol, including chloropalladation and a Heck-like process, proceeds smoothly with good functional group tolerance and high selectivity.

Dual Role of H2O2 in Palladium-Catalyzed Dioxygenation of Terminal Alkenes

A palladium-catalyzed, environmentally friendly dioxygenation reaction of simple alkenes has been developed that enabled rapid assembly of valuable α-hydroxy ketones with high atom economy. Notably, control experiments and 18O isotope-labeling experiments established that H2O2 played a dominant dual role in this transformation.

Synthesis of 2,3-Difunctionalized Benzofuran Derivatives through Palladium-Catalyzed Double Isocyanide Insertion Reaction

A novel palladium-catalyzed tandem cyclization of 1-(allyloxy)-2-ethynylbenzene derivatives with isocyanides in the presence of water has been developed. The key intermediates, benzofuran-3-α-carbonyl aldehydes, were obtained through a simple acid hydrolysis process and could serve as precursors for structurally diverse 2,3-difunctionalized benzofuran derivatives such as important 2-benzofurylquinoxalines, benzofuran-3-α-ketoesters and benzofuryl ynediones. This transformation features convenient operation, simple and commercially available starting materials, broad functional-group compatibility, and moderate to good reaction yields.

Synthesis of 1,4-enyne-3-ones via palladium-catalyzed sequential decarboxylation and carbonylation of allyl alkynoates

Herein we describe a novel protocol for the rapid assembly of 1,4-enyne-3-ones from isocyanides and 1,6-enyne. During this process, two different types of C–C bonds were formed on the same isocyanide carbon atom via sequential decarboxylation, insertion of isocyanide, and reductive elimination. Moreover, this approach shows advantages of mild reaction conditions and excellent functional group compatibility.