93646-29-8

Upstream product

• 97-72-3 2-Methylpropionic anhydride 
• 95-51-2 o-chloroaniline 
• 932-32-1 N-methyl-2-chloroaniline 
• 79-30-1 isobutyryl chloride 

Relevant academic research and scientific papers

Air-stable secondary phosphine oxide as preligand for palladium-catalyzed intramolecular a-arylations with chloroarenes

A palladium catalyst derived from air-stable secondary phosphlne oxide (1-Ad)2P(O)H enabled efficient Intramolecular a-arylations of amides with aryl chlorides, which allowed for the synthesis of diversely substituted (aza)oxindoles.

Synthesis of indolones via radical cyclization of N-(2-halogenoalkanoyl)- substituted anilines

The radical reactions of N-(2-halogenoalkanoyl)-substituted anilines (anilides) of type 1 have been investigated under various conditions. Treatment of compounds 1a-1o with Bu3SnH in the presence of (2,2′-azobis(isobutyronitrile) (AIBN) afforded a mixture of the indolones (oxindoles) 2a-2o and the reduction products 5a-5o (Table 1). In contrast, the N-unsubstituted anilides 1p-1s, 1u, and 1v gave the corresponding reduction products exclusively (Table 1). Similar results were obtained by treatment of 1 with Ni powder (Table 2) or wth Et3B (Table 3). Anilides with longer N-(phenylalkyl) chains such as 6 and 7 were inert towards radical cyclization, with the exception of N-benzyl-2-bromo-N,2-dimethylpropanamide (6b), which, upon treatment with Ni powder in i-PrOH, afforded the cyclized product 9b in low yield (Table 4). Upon irradiation, the extended anilides 6, 7, 10, and 11 yielded the corresponding dehydrobromination products exclusively (Table 5).

Improved catalysts for the palladium-catalyzed synthesis of oxindoles by amide α-arylation. Rate acceleration, use of aryl chloride substrates, and a new carbene ligand for asymmetric transformations

Catalysts comprised Pd(OAc)2 and either PCy3 or sterically hindered N-heterocyclic carbene ligands provide fast rates for a palladium-catalyzed synthesis of oxindoles by amide α-arylation. This catalyst system allowed for room-temperature reactions in some cases and reactions of aryl chlorides at 70 °C. Most important, reactions occurred in high yields under mild conditions to form the quaternary carbon in α,α-disubstituted oxindoles. The combined inter- and intramolecular reaction afforded an efficient synthetic method for formation of α-aryloxindole derivatives. Surprisingly, catalysts containing tert-butylphosphine ligands, which have been most reactive for ketone arylations, were less active than those containing PCy3. Use of new, optically active heterocyclic carbene ligands gave substantial enantioselectivity in formation of an α,α-disubstituted oxindole. In contrast, a variety of optically active phosphine ligands that were tested gave poor enantioselectivity. Mechanistic studies showed that the reaction involves rate-limiting oxidative addition of aryl halide. Base-induced formation of and reductive elimination from an arylpalladium enolate intermediate were both faster than oxidative addition. Deprotonation of the tethered amide appeared to be faster than reductive elimination of the resulting palladium enolate to form the oxindole product.

Photoinduced Cyclizations of Mono- and Dianions of N-Acyl-o-chloroanilines and N-Acyl-o-chlorobenzylamines as General Methods for the Synthesis of Oxindoles and 1,4-Dihydro-3(2H)-isoquinolinones

Formation of the monoanions of a series of N-acyl-N-alkyl-o-chloroanilines by means of LDA in THF followed by irradiation with near-UV light affords 1,3-dialkyloxindoles in good yields.Similar photoinduced cyclizations of dianions derived from N-acyl-o-chloroanilines leads to 3-alkyloxindoles.Photocyclizations of mono- and dianion prepared from α,β-unsaturated o-haloanilides proceed to form 3-alkylideneoxindoles.Carbanions derived from N-acyl-o-chlorobenzylamines also undergo photoassisted ring closure to afford 1,4-dihydro-3(2H)-isoquinolinones.The influence of near-UV light and the effect of inhibitors implicate a radical-chain mechanism as the major reaction pathway in this convenient new method for oxindole and isoquinolinone synthesis.