Catalytic Enantioselective Synthesis of Protecting‐Group‐Free 1,5‐Benzothiazepines

Meninno, Sara; Volpe, Chiara; Lattanzi, Alessandra

doi:10.1002/chem.201700837

Cited by 43 publications

(15 citation statements)

References 47 publications

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“…[22] In 2017, Lattanzi and coworkers reported an organocatalytic asymmetric approach to prepare 2,3dihydro-1,5-benzothiazepinones, starting from α,β-unsaturated pyrazoleamides and 2-aminothiophenols. [23] The protocol consists of a one-pot enantioselective organocatalysed sulfa-Michael reaction of α,β-unsaturated pyrazoleamides with 2-aminothiophenols followed by silica gel catalysed lactamisation (Scheme 8). Working at room temperature, in the presence of only 1 mol% of hydroquinine-derived squaramide 2 b, the one-pot two-step process led to the final N-unprotected heterocycles in high yield and enantioselectivity, without observing other competitive processes.…”

Section: Pyrazoleamides As Electrophiles In Organocatalysismentioning

confidence: 99%

“…In 2017, Lattanzi and coworkers reported an organocatalytic asymmetric approach to prepare 2,3‐dihydro‐1,5‐benzothiazepinones, starting from α,β‐unsaturated pyrazoleamides and 2‐aminothiophenols [23] . The protocol consists of a one‐pot enantioselective organocatalysed sulfa‐Michael reaction of α,β‐unsaturated pyrazoleamides with 2‐aminothiophenols followed by silica gel catalysed lactamisation (Scheme 8).…”

Section: Pyrazoleamides As Electrophiles In Organocatalysismentioning

confidence: 99%

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Pyrazoleamides in Catalytic Asymmetric Reactions: Recent Advances

et al. 2021

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Pyrazoleamides are a class of compounds which have received significant attention in the last years in asymmetric catalysis as more reactive and practical surrogates of esters or amides. These readily available reagents have served in a variety of diastereo-and enantioselective metal-and organocatalytic transformations, spanning from simple carbon-carbon or carbon-heteroatom bond formation to cascade and rearrangement reactions, to produce valuable classes of heterocyclic compounds. More recently, pyrazoleamides have proved to be pertinent reagents in asymmetric catalysis merged with photoredox catalysis, and in more challenging stereoselective bond-forming reactions, occurring directly from a visible-light activated substrate/catalyst complex without any charge separation. Both strategies enable new activation concepts useful for the production of difficult-to-access intermediates and pharmaceuticals. In this review, an overview of the progress achieved in asymmetric catalytic reactions of pyrazoleamides from 2015 up to middle 2020, is illustrated. Rearrangements of α-Diazo Pyrazoleamides 7. Combined Metal-and Organocatalysis 8. Pyrazoleamides in Visible-Light-Activated Photochemical Reactions 8.1. Merging Visible Light Photoredox Activation with Asymmetric Catalysis 8.2. Stereocontrolled Direct Photoreactions from Electronically Excited State 8.3. Merging HAT Photocatalysis with Chiral Lewis Acid Catalysis 9.

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Section: Pyrazoleamides As Electrophiles In Organocatalysismentioning

confidence: 99%

Section: Pyrazoleamides As Electrophiles In Organocatalysismentioning

confidence: 99%

Pyrazoleamides in Catalytic Asymmetric Reactions: Recent Advances

et al. 2021

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“…The scope of the newly established reaction was explored and demonstrated for the synthesis of antidepressant drug (R)-(−)-thiazesim, wherein it provided required product in 93%ee (Scheme 4, entry 1). [32] Meninno et al demonstrated a mild and highly efficient one-pot enantioselective organocatalytic approach for the synthesis of cis-and trans-N-unprotected 2,3-diaryl substituted 1,5-benzothiazepinones (17) from trans-2,3-disubstituted α,β-unsaturated acyl pyrazoles (15) and substituted o-aminothiophenols (1) as starting materials. The synthesis follows two steps, sulfa Michael reaction, and lactamization cascade.…”

Section: Enantioselective Synthesis Of 15-benzothiazepinesmentioning

confidence: 99%

Recent advances in the synthetic chemistry of 1,5‐benzothiazepines: A minireview

Devi

Singh

Monga

2020

Journal of Heterocyclic Chem

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Benzothiazepine, a prominent “drug prejudice core”, is a heterocyclic moiety of immense importance due to its presence in a wide range of bioactive compounds. They act as a primary “biolinker” in diverse synthetic routes to obtain bioactive molecules and serve as important templates in synthetic and medicinal chemistry. They are known to possess a plethora of pharmacological activities, which include Ca2+ channel blockers, CNS acting agents, anti‐HIV, ACE inhibitors, antimicrobial, antifungal, anticancer. Their promising behaviour as drug molecules led the scientific community to develop novel, mild, green, and highly efficient synthetic routes for their synthesis. The conventional synthesis generally involved the condensation of chalcones with 2‐aminothiophenol in the presence of acid/base with high‐temperature heating, mostly resulting in poor yields or mixtures. However, recent trends are replacing these conditions with mild and green conditions through organocatalysis or other methodologies. In this review, an attempt has been made by authors to summarize (a) Recent developments in the synthetic strategies of 1,5‐benzoathiazepines and its derivatives (b) Conventional methods for the synthesis of 1,5‐benzothiazepines including progress in the green chemistry routes (c) Applications of various metals and organocatalysts to achieve the enantioselective synthesis of title compounds.

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“…[19] This reactivity has been exploited to obtain racemic asubstituted carboxylic acid derivatives from different epoxide sources.C orey pioneered an interesting asymmetric variant, involving ring-opening of highly reactive gem-dichloro epoxides,insitu generated from chiral non racemic trichloromethyl carbinols as the starting reagent (Scheme 1e). [20] Despite the undisputed value of the methodologies illustrated in Scheme 1, multi-step preparation of reagents and heterocyclic precursors somewhat limited the practicality and pot-economy of the catalytic variants.T herefore,ao ne-pot process to dihydroquinoxalinones,starting from commercially available compounds and ar eusable catalyst, would significantly fill ag ap in addressing these issues.B uilding on our research interest in the development of stereocontrolled one-pot methodologies to prepare heterocyclic compounds, [21] we envisaged the possibility of setting up an ew streamlined catalytic asymmetric strategy based on Knoevenagel reaction/ asymmetric epoxidation/domino ring-opening cyclization, trusting in the ability of ac hiral non racemic bifunctional organocatalyst to promote the first two steps in astereoselective manner (Scheme 1f). 1-Phenylsulfonyl-1-cyano epoxides were targeted as new potential masked a-halo acyl halide synthons, [22] although either the epoxidation of 1-phenylsulfonyl-1-cyano alkenes and the reactivity of 1-phenylsulfonyl-1-cyano epoxides were unprecedented.…”

Section: Introductionmentioning

confidence: 99%

Catalytic Enantioselective Access to Dihydroquinoxalinones via Formal α‐Halo Acyl Halide Synthon in One Pot

et al. 2021

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An enantioselective one‐pot catalytic strategy to dihydroquinoxalinones, featuring novel 1‐phenylsulfonyl‐1‐cyano enantioenriched epoxides as masked α‐halo acyl halide synthons, followed by a domino ring‐opening cyclization (DROC), is documented. A popular quinine‐derived urea served as the catalyst in two out of the three steps performed in the same solvent using commercially available aldehydes, (phenylsulfonyl)acetonitrile, cumyl hydroperoxide and 1,2‐phenylendiamines. Medicinally relevant 3‐aryl/alkyl‐substituted heterocycles are isolated in generally good to high overall yield and high enantioselectivity (up to 99 % ee). A rare example of excellent reusability of an organocatalyst at higher scale, subjected to oxidative conditions, is demonstrated. Mechanistically, labile α‐ketosulfone has been detected as the intermediate involved in the DROC process. Theoretical calculations on the key epoxidation step rationalize the observed stereocontrol, highlighting the important role played by the sulfone group.

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Catalytic Enantioselective Synthesis of Protecting‐Group‐Free 1,5‐Benzothiazepines

Cited by 43 publications

References 47 publications

Pyrazoleamides in Catalytic Asymmetric Reactions: Recent Advances

Pyrazoleamides in Catalytic Asymmetric Reactions: Recent Advances

Recent advances in the synthetic chemistry of 1,5‐benzothiazepines: A minireview

Catalytic Enantioselective Access to Dihydroquinoxalinones via Formal α‐Halo Acyl Halide Synthon in One Pot

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