Cu-catalyzed C(sp2)-N-bond coupling of boronic acids and cyclic imides

Superfast Formation of C(sp2 )-N, C(sp2 )-P, and C(sp2 )-S Vinylic Bonds in Water Microdroplets

We report examples of C(sp2 )-N, C(sp2 )-S, and C(sp2 )-P bond-forming transformations in water microdroplets at room temperature and atmospheric pressure using N2 as a nebulizing gas. When an aqueous solution of vinylic acid and amine is electrosprayed (+3 kV), the corresponding C(sp2 )-N product is formed in a single step, which was characterized using mass spectrometry (MS) and tandem mass spectrometry (MS2 ). The scope of this reaction was extended to other amines and other unsaturated acids, including acrylic (CH2 =CHCOOH) and crotonic (CH3 CH=CHCOOH) acids. We also found that thiols and phosphines are viable nucleophiles, and the corresponding C(sp2 )-S and C(sp2 )-P products are observed in positive ion mode using MS and MS2 .

Organocatalytic cascade nucleophilic/aza-Michael addition reactions: metal-free catalytic strategy for the synthesis of hydantoins

Lewis base-catalyzed cascade nucleophilic/aza-Michael addition reaction of N-alkoxy β-oxo-acrylamides with isocyanates has been developed to afford various highly functionalized hydantoin derivatives in 80-98% yields under mild reaction conditions. The intriguing features of this method include metal-free reaction conditions, low catalyst loading, broad substrate scope and short reaction time.

CuF2/DMAP-Catalyzed N-Vinylation: Scope and Mechanistic Study

CuF₂/DMAP has been established as an excellent catalytic system for vinylsilane-promoted N-vinylation of amides and azoles at room temperature without an external fluoride source. A mechanism has been proposed on the basis of the isolation of reactive intermediate [Cu(DMAP)₄Cl₂], fluoride ion-assisted transmetalation, and ultraviolet-visible spectroscopic studies. The catalytic efficiency of the synthesized and structurally characterized [Cu(DMAP)₄Cl₂] complex has been demonstrated. The valuable monomers for water-soluble polymers, viz., NVP, NVC, and NVIBA, were synthesized on a gram scale.

Construction of sulfur-containing N-vinylimides: N-addition of imides to propargyl sulfonium salts

An N-addition reaction between imides and propargyl sulfonium salts was developed to afford sulfur-containing N-vinylimides with moderate to excellent yields. Under the activation of NaOAc·3H₂O, imides could undergo deprotonation and propargyl sulfonium salts could isomerize to allenic sulfonium salts. The N-nucleophilic attack initiates the reaction and gives the desired products. Various imides, including arylimides, aliphatic imides and N-(arylsulfonyl) alkyl acylamides, and even bioactive saccharin, thalidomide and pomalidomide could provide organosulfur N-vinylimides compounds. The simple, mild and metal-free reaction conditions, the broad scope of substrates, gram-scale synthesis and convenient transformation embody the synthetic superiority of this process.

An N-addition reaction between imides and propargyl sulfonium salts was developed to afford sulfur-containing N-vinylimides with moderate to excellent yields.