Pd-Catalyzed Heck-Type Cascade Reactions with N-Tosyl Hydrazones: An Efficient Way to Alkenes via in Situ Generated Alkylpalladium

Abstract

A palladium-catalyzed Heck-type cascade reaction of aryl halides and N-tosyl hydrazones is reported. The neopentylpalladium species, generated from an intramolecular Heck-type insertion reaction of aryl halides, could efficiently react with carbenes to form highly functionalized alkenes. The synthesis of spiro compounds was also explored via a multiple Heck-type insertion reaction with N-tosyl hydrazone.

Domino Carbopalladation/CH Functionalization Sequence: An Expedient Synthesis of Bis‐Heteroaryls through Transient Alkyl/Vinyl–Palladium Species Capture

“…To develop this domino protocol, the conditions must be carefully selected to avoid the direct heteroarylation as an unwanted side reaction. We started our investigations for the synthesis of indolinone–azole framework by attempting the intermolecular cyclization using 1 a , which was easily prepared from 2‐iodoaniline,5d and 2‐phenyl‐1,3,4‐oxadiazole ( 2 a ) as model substrates in toluene for 12 h at 100 °C (Table 1). [Pd(PPh 3 ) 4 ] proved to be a superior catalyst to Pd(OAc) 2 for the reaction (entries 1–5).…”

Advances in Palladium‐Catalyzed Cascade Cyclizations

“…Gu and co-workers reported acarbopalladation/carbene insertion for the synthesis of benzo-fused carboand heterocycles 177 (Scheme 52). [73] Thei nitial intramolecular carbopalladationf orms the benzo-fused quiring ac hange in reaction conditions.F urthermore, various Ar groups were shownt ob ec ompatible,w ith the exception of para-nitrophenyl which did not provide the desired product.…”

Pd-Catalyzed Highly Regio- and Stereoselective Formation of C–C Double Bonds: An Efficient Method for the Synthesis of Benzofuran-, Dihydrobenzofuran-, and Indoline-Containing Alkenes

“…The residue was separated by column chromatography on a silica gel with petroleum ether/ethyl acetate as the 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 eluent to afford the corresponding products 1h, 1j. 34 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 and extracted with EtOAc twice. The combined organic layer was washed with brine and dried over Na 2 SO 4 , filtered and concentrated.…”

“…34 To a suspension of NaH (100 mg, 60% in oil, 2 mmol) in DMF (10 mL) were added 0.52 g (2 mmol) of N-(2-iodophenyl)acetamide in DMF (5 mL). When the evolution of H 2 has ceased, methallyl chloride (0.4 mL, 4 mmol) was added.…”