Scheme 12. Three-component reactiono fa-halo-N-tosylhydrazones,indoles and arylboronic acids.Scheme 13. Total synthesis of avrainvilleol.Scheme14. Synthesis of dienes from allenylboronic acids.Scheme 55. ClassicF ischer indole reaction with N-tosylhydrazones.Scheme56. Synthesis of 1H-indazoles via ab enzyne intermediate.Scheme57. Proposed mechanism for the synthesis of 1H-indazoles.

An efficient diastereoselective synthesis of α-tetralone-fused spirooxindoles is reported. The Pd-catalyzed domino reaction proceeds through a carbene migratory insertion followed by a 6-endo-trig mode of conjugate addition sequence from easily accessible isatin-derived N-tosylhydrazones and 2'-iodochalcones. The versatility of the protocol has been showcased by high functional group tolerance, broad substrate scope, and extension to an expedient synthesis of spiroacenaphthylenes. NMR reaction profiling and deuterium-labeling investigations provide insight into the mechanistic pathway.

A heterogeneous Pd/C catalyzed three component protocol is developed for the sulfoximinocarbonylation of aryl halides.

A facile synthesis of indanone-fused spirooxindoles is disclosed by directing the reactivity of η-oxoallyl Pd-intermediate toward 5- exo-trig mode of cyclization. The Pd-catalyzed reaction of the rationally designed starting material 3-arylidene oxindoles with isatin-derived tosylhydrazone afforded the spirooxindoles having all-carbon quaternary center through carbene migratory insertion followed by Heck-type cyclization sequence. The photophysical studies and DFT calculations were conducted to understand their electronic properties. Moreover, the synthesis of XEN 907 analogue is also featured by employing the present methodology.