01565nas a2200193 4500008004100000245016700041210007100208260000800279300001600287490000700303520077100310100003001081700002301111700002901134700002401163700002401187700002101211856013901232 2023 eng d00aOrganocatalysed one-pot three component synthesis of 3,3′-disubstituted oxindoles featuring an all-carbon quaternary center and [spiro 2H-pyran-3,4′-indoline]0 aOrganocatalysed onepot three component synthesis of 33′disubstit cAPR a13206-132120 v133 a

A simple and efficient methodology for the one-pot synthesis of 3,3 `-disubstituted oxindoles featuring an all-carbon quaternary center has been demonstrated through l-proline catalysed three-component reaction based on sequential Knoevenagel condensation/Michael addition and also one-pot synthesis of spiro[2H-pyran-3,4 `-indoline] through consecutive Knoevenagel condensation/Michael addition/reduction/cyclization reactions from readily available isatin derivatives, malononitrile, and ketones. The present methodology presents several advantages, including simple reaction set-up, short reaction times, and easy to work-up. Also, this strategy offers broad substrate scope with excellent yields and high atom economy, under mild reaction conditions.

1 aNichinde, Chandrakant, B.1 aPatil, Baliram, R.1 aChaudhari, Suryakant, S.1 aMali, Bhupendra, P.1 aGonnade, Rajesh, G.1 aKinage, Anil, K. uhttps://library.ncl.res.in/content/organocatalysed-one-pot-three-component-synthesis-33%E2%80%B2-disubstituted-oxindoles-featuring-all01810nas a2200205 4500008004100000022001400041245012800055210006900183260000800252300001400260490000700274520103600281100002901317700003001346700002301376700002801399700002601427700002101453856013001474 2024 eng d a1477-052000aBase controlled rongalite-mediated reductive aldol/cyclization and dimerization of isatylidene malononitriles/cyanoacetates0 aBase controlled rongalitemediated reductive aldolcyclization and cFEB a1727-17320 v223 a

In this study, we developed a novel methodology involving a base-controlled, rongalite-mediated reductive/aldol reaction, followed by cyclization of isatylidene malononitriles/cyanoacetates, resulting in the synthesis of spiro[2,3-dihydrofuran-3,3 `-oxindole]. Additionally, we have disclosed a rongalite-mediated dimerization process for isatylidene malononitriles, yielding dispiro[cyclopent-3 `-ene]bisoxindole. The utilization of rongalite in this reaction serves a dual purpose, acting both as a reducing agent and a C1 synthon. The developed approach has several advantages like a simple reaction setup, a wide substrate scope, requiring less time, using water as a green solvent, no metal or catalyst is required and products can be easily isolated via filtration with excellent yields under mild reaction conditions. A novel methodology was developed for the synthesis of spiro[2,3-dihydrofuran-3,3 `-oxindole] and dispiro[cyclopent-3 `-ene]bisoxindole under mild reaction conditions using inexpensive reagents.

1 aChaudhari, Suryakant, S.1 aNichinde, Chandrakant, B.1 aPatil, Baliram, R.1 aGirase, Amardipsing, S.1 aKrishna, Gamidi, Rama1 aKinage, Anil, K. uhttps://library.ncl.res.in/content/base-controlled-rongalite-mediated-reductive-aldolcyclization-and-dimerization-isatylidene01410nas a2200181 4500008004100000245015700041210007100198260000800269300001400277490000700291520066600298100002300964700003000987700002901017700002601046700002101072856013501093 2024 eng d00aOrganocatalyzed [4+2] cycloaddition of α,β-unsaturated ketones and isatylidene malononitrile: accessing spiro[3-arylcyclohexanone]oxindole derivatives0 aOrganocatalyzed 42 cycloaddition of αβunsaturated ketones and is cJAN a2873-28770 v143 a

Herein, we developed a series of compounds featuring spiro[3-arylcyclohexanone]oxindoles through Barbas [4 + 2] cycloaddition reactions between isatylidene malononitrile and alpha,beta-unsaturated ketones using l-proline as an organocatalyst. The reported methodology offers many advantages such as mild reaction conditions, diverse substrate scope with high yields, easy reaction setup, and use of easily synthesizable starting materials. An l-proline catalyzed-Barbas-[4 + 2]-cycloaddition reaction is reported for the synthesis of spiro[3-arylcyclohexanone]oxindole derivatives. The method can tolerate a diverse substrate scope with high yields.

1 aPatil, Baliram, R.1 aNichinde, Chandrakant, B.1 aChaudhari, Suryakant, S.1 aKrishna, Gamidi, Rama1 aKinage, Anil, K. uhttps://library.ncl.res.in/content/organocatalyzed-42-cycloaddition-%CE%B1%CE%B2-unsaturated-ketones-and-isatylidene-malononitrile01674nas a2200193 4500008004100000022001400041245019100055210006900246260000800315300001400323490000700337520088200344100002301226700003001249700002801279700002901307700002101336856012301357 2025 eng d a1477-052000aConjugate addition/cyclization of propanal with isatylidene malononitriles: an efficient one-pot organocatalytic approach for the synthesis of 3′-methyl spiro[2H-pyran-3,4′-indoline]0 aConjugate additioncyclization of propanal with isatylidene malon cJUN a6214-62190 v233 a

The organocatalyzed one-pot Michael addition reaction of propanal to isatylidene malononitriles remains largely unexplored due to challenges in controlling the reaction and preventing side processes such as aldol condensation, self-aldolization, and 1,3-dipolar cycloaddition. In this study, we introduce a one-pot methodology for the synthesis of 3 `-alkyl spiro[2H-pyran-3,4 `-indoline] via an organocatalyzed Michael addition of simple propanal to isatylidene malononitrile derivatives, which are generated in situ from isatin derivatives and malononitrile. Subsequent reduction of the Michael adduct with NaBH4 leads to the target product with high efficiency under mild conditions. This strategy offers several advantages, including environmental sustainability, high to excellent yields, shorter reaction times, cost-effectiveness, and ease of implementation.

1 aPatil, Baliram, R.1 aNichinde, Chandrakant, B.1 aGirase, Amardipsing, S.1 aChaudhari, Suryakant, S.1 aKinage, Anil, K. uhttps://library.ncl.res.in/content/conjugate-additioncyclization-propanal-isatylidene-malononitriles-efficient-one-pot01901nas a2200265 4500008004100000022001400041245014500055210007200200260000800272300001500280490000700295520084600302653003301148653004301181653004701224653002201271653004001293653002901333100002901362700003001391700002301421700002801444700002101472856014201493 2025 eng d a2365-654900aEfficient synthesis of 3,3′-Spirooxindole γ-Butyrolactone via Rongalite-mediated domino reductive aldol and spiro-lactonization reactions0 aEfficient synthesis of 33′Spirooxindole γButyrolactone via Ronga cFEB ae2024059960 v103 a

In this study, we develop a novel methodology involving rongalite-mediated domino reductive/aldol reaction, followed by spiro-lactonization of 2-oxoindolin-3-ylidene acetates/malonates in presence of base to synthesis of 3,3 `-spirooxindole gamma-butyrolactone. The detail study, such as effect of solvent, effect of different base and substrate has been carried out. Scale up of this methodology is also done. Sodium hydroxymethanesulfinate dihydrate (rongalite) concurrently has a dual role in this context; it acts as a reducing agent as well as C1 synthon. This approach offers several advantages, such as being metal- and catalyst-free, involving a simple reaction protocol, having a wide substrate scope, using water as a green solvent, and providing good to excellent yields of the products under mild reaction conditions.

10a(+/-) Coixspirolactam A & [310a3 `-spirooxindole gamma-butyrolactone]10aDomino reductive/aldol/spiro-lactonization10aGood step economy10aRongalite as reductant & C1 synthon10aWater as a green solvent1 aChaudhari, Suryakant, S.1 aNichinde, Chandrakant, B.1 aPatil, Baliram, R.1 aGirase, Amardipsing, S.1 aKinage, Anil, K. uhttps://library.ncl.res.in/content/efficient-synthesis-33%E2%80%B2-spirooxindole-%CE%B3-butyrolactone-rongalite-mediated-domino-reductive01595nas a2200205 4500008004100000022001400041245012900055210006900184260000800253300001400261490000700275520082600282100002901108700003001137700002301167700002801190700002501218700002101243856012501264 2025 eng d a1477-052000aRongalite-promoted self-dimerization of 3-acylidene-2-oxindoles: a diastereoselective route to synthesis of bispirooxindoles0 aRongalitepromoted selfdimerization of 3acylidene2oxindoles a dia cOCT a8687-86940 v233 a

A facile and efficient one-pot rongalite-mediated self-dimerization of 3-acylidene-2-oxindoles has been developed for the diastereoselective synthesis of highly functionalized dispirocyclopentanebisoxindoles. The reaction proceeds via a domino sequence involving intermolecular Michael addition followed by intramolecular aldol cyclization under basic conditions. Rongalite, an inexpensive and readily available reagent (similar to\$0.03 per g), plays a crucial role in promoting the transformation, offering significant advantages such as operational simplicity, step economy, scalability to gram-scale synthesis, and potential for post-functionalization. This methodology provides an efficient route to structurally complex oxindole frameworks with high stereocontrol, demonstrating broad synthetic utility.

1 aChaudhari, Suryakant, S.1 aNichinde, Chandrakant, B.1 aPatil, Baliram, R.1 aGirase, Amardipsing, S.1 aKaulage, Sandeep, H.1 aKinage, Anil, K. uhttps://library.ncl.res.in/content/rongalite-promoted-self-dimerization-3-acylidene-2-oxindoles-diastereoselective-route01906nas a2200277 4500008004100000022001400041245017200055210006900227260000800296490000700304520082900311653003601140653004501176653002501221653002001246653005401266100003001320700001701350700002801367700002301395700002901418700002601447700001801473700002101491856011601512 2025 eng d a1434-193X00aSequential nitro-michael addition and reductive cyclization cascade reaction for diastereoselective synthesis of multifunctionalized 3,3′-pyrrolidinyl-spirooxindoles0 aSequential nitromichael addition and reductive cyclization casca cFEB0 v283 a

In this investigation, we elucidated, one-pot two stage efficient synthesis of multifuctionalized spiro[oxindole -3,3 `-pyrrolidine]. The methodology proceeds via organocatalyzed nitro-Michael addition reaction between indolylidenecyanoesters and nitroalkanes to formed nitro-Michael adduct which transformed into multifunctionalized 3,3 `-pyrrolidinyl-spirooxindoles by metal catalyzed reductive cyclization cascade. DFT investigations were conducted to elucidate the mechanism underlying the preferential reduction of the nitro group, with subsequent attack on the nitrile and ester groups remain inert throughout the reaction process. The approach is operationally simple, easily scalable, exhibits compatibility with readily accessible starting material and catalysts, thereby emphasizing cost-effectiveness.

10a3 `-pyrrolidinyl spirooxindoles10aDFT study for regioselective cyclization10aDiastereoselective 310aorganocatalysis10aPd/C catalysed partial reductive spirocyclization1 aNichinde, Chandrakant, B.1 aBhati, Meema1 aGirase, Amardipsing, S.1 aPatil, Baliram, R.1 aChaudhari, Suryakant, S.1 aGamidi, Rama, Krishna1 aJoshi, Kavita1 aKinage, Anil, K. uhttps://library.ncl.res.in/content/sequential-nitro-michael-addition-and-reductive-cyclization-cascade-reaction01460nas a2200181 4500008004100000245010600041210006900147260000900216300001400225490000700239520077400246100002301020700003001043700002801073700002901101700002101130856012701151 2026 eng d00aThiophenol-mediated metal-free chemoselective conjugate reduction strategy for 3-alkylidene oxindoles0 aThiophenolmediated metalfree chemoselective conjugate reduction  cFEB  a7702-77060 v163 a

A mild and metal-free thiophenol-mediated chemoselective conjugate reduction of 3-alkylidene oxindoles via a thiol-ene-type Michael addition was effectively carried out. Thiophenol as an efficient reductant is used in DMSO, and the transformation proceeds without the need for metal catalyst, external hydrogen source, or harsh reagents. The reaction displays a broad substrate scope, accommodating both electron-donating and electron-withdrawing substituents, and delivers 3-alkyloxindoles in high yields with excellent beta-selectivity. This sustainable and operationally simple method unveils a distinct thiol-mediated reduction mechanism, providing a green and versatile approach for accessing reduced oxindole derivatives and related Michael acceptors.

1 aPatil, Baliram, R.1 aNichinde, Chandrakant, B.1 aGirase, Amardipsing, S.1 aChaudhari, Suryakant, S.1 aKinage, Anil, K. uhttps://library.ncl.res.in/content/thiophenol-mediated-metal-free-chemoselective-conjugate-reduction-strategy-3-alkylidene