A DBU-catalyzed one-pot cascade reaction of propargylamines and water for the synthesis of flavanones has been developed. This process proceeds via a sequence of 1,4-conjugate addition of water to alkynyl o-quinone methide (o-AQM), followed by the alkyne–allene isomerization and subsequent intramolecular oxa-Michael addition. This strategy provides a convenient method for accessing a broad range of flavanones in good to excellent yields with good functional-group tolerance, in particular, the reactive halo functional groups.

A simple, general route to the 2,3-dihydrobenzofurans substituted at C3 by an aryethynyl or aryl group, starting from propargylamine and its derivatives with benzoyl sulfonium salts, has been developed. This reaction involved an in situ generated o-quinone methide (o-QM) intermediate followed by [4+1] annulation with sulfur ylides. Notably, this protocol's features include moderate to excellent yields and remarkable diastereoselectivity (>20:1 dr in general), easy performance, as well as applicability to versatile 2,3dihydrobenzofurans with aryethynyl or an aryl group via C−C and C−O bond formation in one pot without any catalyst in an aqueous mixed solvent.

A novel and one‐pot domino reaction of propargylamines with benzoylacetonitriles and β‐keto esters for the regiospecific synthesis of polysubstituted furans and furo[3,4‐c]coumarins has been developed. The reaction is believed to proceed by sequential 1,4‐conjugate addition of benzoylacetonitriles/β‐keto esters to propargylamines, 5‐exo‐dig annulation/isomerization to form the fully substituted furans, and intramolecular transesterification to furo[3,4‐c]coumarin skeleton. The features of this method include inexpensive base, readily available substrates, high regioselectivity, and convenient operation. A wide variety of densely functionalized furans and furocoumarins are furnished by one‐pot domino process and transition‐metal free methods in moderate to good yields, respectively.magnified image

A novel and efficient strategy has been developed for the synthesis of 3-triazolylcoumarins in a one-pot, copper-catalyzed multicomponent reaction involving a cascade reaction of salicylaldehydes, ethyl 2-azidoacetate, and arylacetylenes.

A novel and mild Rh(iii)-catalyzed cascade C–H activation/intramolecular condensation of 1-aryl-1H-pyrazol-5-amines with cyclic 2-diazo-1,3-diketones for the synthesis of various important benzo[f]pyrazolo[1,5-a][1,3]diazepines has been developed.