Rhodium-Catalyzed Tandem Reaction of Isocyanides with Azides and Oxygen Nucleophiles: Synthesis of Isoureas.

A novel rhodium-catalyzed tandem reaction of isocyanides with azides and various oxygen nucleophiles has been developed. The reaction provides a simple and highly efficient one-pot synthesis of various N-sulfonyl/acylisoureas with broad substrate scope in an atom-economical manner from readily available starting materials in a highly stereoselective manner.

Activation of α-diazocarbonyls by organic catalysts: diazo group acting as a strong N-terminal electrophile.

For the first time α-diazocarbonyls have been used as highly active N-terminal electrophiles in the presence of bicyclic amidine catalysts. The CN bond-forming reactions of active methylene compounds as C nucleophiles with α-diazocarbonyls as N-terminal electrophiles proceed quickly under ambient conditions, in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), because of the formation of the reactive N-terminal electrophilic intermediates. DBU activates both the active methylene and α-diazocarbonyl. Importantly, this reaction is general for both active methylenes and α-diazocarbonyls, and the activation mode will lead to new synthetic applications of α-diazocarbonyls.

A base-catalyzed cycloisomerization of 5-cyano-pentyne derivatives: an efficient synthesis of 3-cyano-4,5-dihydro-1H-pyrroles.

A base-catalyzed cycloisomerization of 5-cyano-pentyne bearing a terminal alkyne group has been developed under metal-free conditions. This reaction involves a tandem process providing efficient access to 3-cyano-4,5-dihydro-1H-pyrroles in good to excellent yields in an atom-economic manner with 1,3-cyano migration as the key transformation.