1463045-59-1Relevant academic research and scientific papers
Pd(0)-Catalyzed Chemoselective Deacylative Alkylations (DaA) of N-Acyl 2-Oxindoles: Total Syntheses of Pyrrolidino[2,3- b]indoline Alkaloids, (±)-Deoxyeseroline, and (±)-Esermethole
Kumar, Nivesh,Gavit, Vipin R.,Maity, Arindam,Bisai, Alakesh
, p. 10709 - 10735 (2018/09/29)
We report an efficient Pd(0)-catalyzed deacylative allylation of N-acyl 3-substituted 2-oxindoles via the coupling of in situ generated nucleophiles (3 and 4) with allyl electrophiles for the synthesis of a variety of 2-oxindoles with C3-quaternary centers. Gratifyingly, this alkylation process is found to be highly chemoselective in nature, where a C-C bond formation is completely predominant over a C-N bond formation. A variety of key intermediates were synthesized utilizing an aforementioned methodology.
FeCl3-Catalyzed Allylation Reactions onto 3-Hydroxy-2-oxindoles: Formal Total Syntheses of Bis-cyclotryptamine Alkaloids, (±)-Chimonanthine, and (±)-Folicanthine
Kinthada, Lakshmana K.,Medisetty, Sai Raghavendra,Parida, Amarchand,Babu, K. Naresh,Bisai, Alakesh
, p. 8548 - 8567 (2017/08/23)
An FeCl3-catalyzed efficient strategy for the allylation reactions of 3-hydroxy-2-oxindoles with allyltrimethylsilane has been developed. The reaction affords a variety of 2-oxindoles having quaternary center at the pseudobenzylic position in an operationally simple and inexpensive procedure. Control experiments using enantioenriched 3-hydroxy-2-oxindole show that the reaction proceeds through in situ generated 2H-indol-2-one (8). The methodology presents an efficient and concise access to the pyrroloindoline alkaloids (±)-deoxyeseroline (1a), (±)-esermethole (1b), (±)-physostigmine (1c), (±)-phenserine (1d), and (±)-physovenine (1e). Eventually, we extrapolated the scope of this methodology to the formal total syntheses of dimeric cyclotyrptamine alkaloids (±)-chimonanthine (3a), (±)-folicanthine (3c), and (±)-calycanthine (4).
Friedel-Crafts alkylations of electron-rich aromatics with 3-hydroxy-2-oxindoles: Scope and limitations
Kinthada, Lakshmana K.,Ghosh, Santanu,Babu, K. Naresh,Sharique, Mohd.,Biswas, Soumava,Bisai, Alakesh
, p. 8152 - 8173 (2015/01/08)
A Lewis acid-catalyzed nucleophilic addition of electron rich aromatics with 3-hydroxy-2-oxindoles 5 was developed. The reaction is believed to proceed through the 2H-indol-2-one ring system 9, which eventually reacts with various electron-rich aromatics to afford a variety of 2-oxindoles with an all-carbon quaternary center at the pseudobenzylic position (4, 8, 13, and 16) in high yields. The methodology provides an expeditious route to the tetracyclic core (3) of diazonamide (1), and azonazine (2) as well as the tricyclic core of asperazine (6a), idiospermuline (6b), and calycosidine (6c) viz. C(3a)-arylpyrroloindolines 7 having an all-carbon quaternary center on further synthetic elaboration.
Acid-catalyzed reactions of 3-hydroxy-2-oxindoles with electron-rich substrates: Synthesis of 2-oxindoles with all-carbon quaternary center
Kinthada, Lakshmana K.,Ghosh, Santanu,De, Subhadip,Bhunia, Subhajit,Dey, Dhananjay,Bisai, Alakesh
, p. 6984 - 6993 (2013/10/08)
A Lewis acid catalyzed reaction of in situ generated 2H-indol-2-one (9) with various 2π and other electron-rich substrates has been developed. A variety of electron-rich substrates such as allyl/methallyltrimethylsilane, phenylacetylene, styrenes, acetophenone, and indoles have been used. The methodology provides a straightforward approach for the synthesis of 2-oxindoles with an all-carbon quaternary center at the pseudobenzylic position.
