An efficient method for the synthesis of dihydrobenzo[d]isoxazoles and dihydrobenzo[d]oxazoles bearing a quaternary carbon center has been developed. The reaction involves generation of a ketonitrone intermediate in situ from a ketoxime and an aryne. A novel thermal rearrangement of the dihydrobenzo[d]isoxazole products to the corresponding dihydrobenzo[d]oxazoles has been observed. These transformations tolerate a variety of functional groups and offer a rapid and efficient way to diverse dihydrobenzo[d]isoxazoles and dihydrobenzo[d]oxazoles under mild transition-metal-free conditions.

A novel palladium-catalyzed domino Heck/aryne carbopalladation/C–H functionalization reaction using in situ generated arynes has been developed in which three new C–C bonds and a carbon quaternary center are formed. This methodology affords moderate to excellent yields of heterocycle-fused 9,10-dihydrophenanthrenes.

A highly efficient Pd-catalyzed Heck-type cascade process with 2-(1-alkynyl)benzaldimines has been developed, which provides access to a broad range of 4-alkylated isoquinoline derivatives in moderate to good yields. The σ-alkylpalladium(II) intermediate in the Heck reaction activates alkynes toward intramolecular nucleophilic attack. This is the first example of a σ-alkylpalladium(II) intermediate promoting the cyclization of alkynes containing a proximate nucleophilic center.

A novel palladium-catalyzed annulation reaction of in situ generated arynes and o-halostyrenes has been developed. This methodology affords moderate to excellent yields of substituted phenanthrenes and is tolerant of a variety of functional groups such as nitrile, ester, amide, and ketone. This annulation chemistry has been successfully applied to the formal total synthesis of a biologically active alkaloid (±)-tylophorine.

A highly efficient Pd-catalyzed Heck-type cascade process with 2-(1-alkynyl)benzaldimines has been developed, which provides access to a broad range of 4-alkylated isoquinoline derivatives in moderate to good yields. The σ-alkylpalladium(II) intermediate in the Heck reaction activates alkynes toward intramolecular nucleophilic attack. This is the first example of a σ-alkylpalladium(II) intermediate promoting the cyclization of alkynes containing a proximate nucleophilic center.