0000000000135524
AUTHOR
Suruchi Mahajan
Diastereoselective Synthesis of Spiro[pyrazolone-4,3′-tetrahydrothiophenes] via a Sulfa-Michael/Aldol Domino Reaction
Synthesis : journal of synthetic organic chemistry 48(23), 4091-4098(2016). doi:10.1055/s-0035-1562473
Asymmetric Synthesis of Spiro β-Lactamsviaa Squaramide- Catalyzed Sulfa-Michael Addition/Desymmetrization Protocol
An efficient asymmetric synthesis of spirocyclohexenone β-lactams bearing three contiguous stereocenters has been achieved in moderate to good yields and high stereoselectivities. The protocol involves the combination of a squaramide-catalyzed sulfa-Michael addition under desymmetrization via a dynamic kinetic resolution of racemic 2,5-cyclohexadienones.
Organocatalytic Asymmetric Synthesis of 2,3′-Connected Bis-Indolinones by Mannich Reactions of N-Acetylindolin-3-ones with Isatin N-Boc Ketimines
A highly diastereo- and enantioselective Mannich reaction of N-acetylindolin-3-ones with isatin N-Boc ketimines to form 2,3′-connected bis-indolinones is developed employing a low loading of a readily available bifunctional thiourea catalyst. The asymmetric synthesis connects two indolinones via a vic-diamine unit and generates two neighboring stereocenters.
Asymmetric Synthesis of Spiro Tetrahydrothiophene-indan-1,3-diones via a Squaramide-Catalyzed Sulfa-Michael/Aldol Domino Reaction
Synthesis 48(08), 1131-1138(2016). doi:10.1055/s-0035-1560412
Enantioselective synthesis of pyrazolone α-aminonitrile derivatives via an organocatalytic Strecker reaction
A new organocatalytic enantioselective Strecker reaction of pyrazolone-derived ketimine electrophiles has been developed. Using pseudo-enantiomeric squaramide catalysts the nucleophilic 1,2-addition of trimethylsilyl cyanide to the ketimines efficiently provides a direct entry to both enantiomers of pyrazolone α- aminonitrile derivatives at will in good yields and high enantioselectivities for a wide variety of substrates. peerReviewed
Squaramide-Catalyzed Asymmetric aza-Friedel-Crafts/N,O-Acetalization Domino Reactions Between 2-Naphthols and Pyrazolinone Ketimines
N-Boc ketimines derived from pyrazolin-5-ones were explored to develop an unprecedented domino aza-Friedel-Crafts/N,O-acetalization reaction with 2-naphthols. The novel method requires a catalyst loading of only 0.5 mol % of a bifunctional squaramide catalyst, is scalable to gram amounts, and provides a new series of furanonaphthopyrazolidinone derivatives bearing two vicinal tetra-substituted stereogenic centers in excellent yields (95-98 %) and stereoselectivity (>99:1 d.r. and 97-98 % ee). A different reactivity was observed in the case of 1-naphthols and other electron-rich phenols, which led to the aza-Friedel-Crafts adducts in 70-98 % yield and 47-98 % ee.
Palladium Catalyzed [3+2] Cycloaddition of Vinyl Aziridine and Indane-1,3-diones: Diastereo- and Enantioselective Access to Spiro-Pyrrolidines
A mild and efficient palladium-catalyzed [3+2] cycloaddition of vinylaziridine and indane-1,3-diones has been realized. The resulting spiro-pyrrolidines were provided in excellent yields and, with the introduction of the leucine-derived phosphine ligand, moderate to good enantio- and diastereoselectivities.
Asymmetric Synthesis of Amino-Bis-Pyrazolone Derivatives via an Organocatalytic Mannich Reaction.
A new series of N-Boc ketimines derived from pyrazolin-5-ones have been used as electrophiles in asymmetric Mannich reactions with pyrazolones. The amino-bis-pyrazolone products are obtained in excellent yields and stereoselectivities by employing a very low loading of 1 mol % of a bifunctional squaramide organocatalyst. Depending on the substitution at position 4 of the pyrazolones, the new protocol allows for the generation of one or two tetrasubstituted stereocenters, including a one-pot version combing the Mannich reaction with a base-mediated halogenation. peerReviewed
CCDC 1542055: Experimental Crystal Structure Determination
Related Article: Suruchi Mahajan, Pankaj Chauhan, Uğur Kaya, Kristina Deckers, Kari Rissanen, Dieter Enders|2017|Chem.Commun.|53|6633|doi:10.1039/C7CC02874A
CCDC 1975968: Experimental Crystal Structure Determination
Related Article: Fabrizio Vetica, Stephen J. Bailey, Mukesh Kumar, Suruchi Mahajan, Carolina von Essen, Kari Rissanen, Dieter Enders|2020|Synthesis|52|2038|doi:10.1055/s-0040-1707472
CCDC 1484545: Experimental Crystal Structure Determination
Related Article: Ugur Kaya, Suruchi Mahajan, Jan-Hendrik Schöbel, Arto Valkonen, Kari Rissanen and Dieter Enders|2016|Synthesis|48|4091|doi:10.1055/s-0035-1562473
CCDC 1543566: Experimental Crystal Structure Determination
Related Article: V. Pratap Reddy Gajulapalli, Ehsan Jafari, Dipti Sankar Kundu, Suruchi Mahajan, Anssi Peuronen, Kari Rissanen, Dieter Enders|2017|Synthesis|49|4986|doi:10.1055/s-0036-1590823
CCDC 1537523: Experimental Crystal Structure Determination
Related Article: Pankaj Chauhan, Suruchi Mahajan, Uğur Kaya, Anssi Peuronen, Kari Rissanen, and Dieter Enders|2017|J.Org.Chem.|82|7050|doi:10.1021/acs.joc.7b01113
CCDC 1537522: Experimental Crystal Structure Determination
Related Article: Pankaj Chauhan, Suruchi Mahajan, Uğur Kaya, Anssi Peuronen, Kari Rissanen, and Dieter Enders|2017|J.Org.Chem.|82|7050|doi:10.1021/acs.joc.7b01113
CCDC 1437740: Experimental Crystal Structure Determination
Related Article: Suruchi Mahajan, Pankaj Chauhan, Marcus Blümel, Rakesh Puttreddy, Kari Rissanen, Gerhard Raabe, Dieter Enders|2016|Synthesis|48|1131|doi:10.1055/s-0035-1560412
CCDC 1476009: Experimental Crystal Structure Determination
Related Article: Pankaj Chauhan, Suruchi Mahajan, Uğur Kaya, Arto Valkonen, Kari Rissanen and Dieter Enders|2016|Adv.Synth.Catal.|358|3173|doi:10.1002/adsc.201600554
CCDC 1572983: Experimental Crystal Structure Determination
Related Article: Uğur Kaya, Pankaj Chauhan, Suruchi Mahajan, Kristina Deckers, Arto Valkonen, Kari Rissanen, Dieter Enders|2017|Angew.Chem.,Int.Ed.|56|15358|doi:10.1002/anie.201709224