Dearomative [4 + 2] cycloaddition of 3‐nitroindoles with ortho‐amino Morita−Baylis−Hillman carbonates to forge indole‐fused quinolines

Journal of Heterocyclic Chemistry, Journal Year: 2024, Volume and Issue: 61(3), P. 528 - 537

Published: Jan. 16, 2024

Abstract A dearomative [4 + 2] cycloaddition of 3‐nitroindoles ortho ‐amino Morita−Baylis−Hillman carbonates was established under mild conditions. This method provides an efficient and practical approach for delivering tetrahydro‐5 H ‐indolo[2,3‐ b ]quinolines containing three contiguous stereocenters, two tertiary one quaternary, in high yield (up to 95%) with excellent diastereoselectivity (all cases >25:1 dr ). The potential synthetic applications this strategy were also highlighted by the scale‐up experiment further transformation. Moreover, structure relative configuration cycloadduct unequivocally confirmed single‐crystal X‐ray diffraction.

Language: Английский

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Substrate-controlled [4+1] and [3+2] annulations of ninhydrin-derived Morita–Baylis–Hillman carbonates to access polysubstituted furans and cyclopentenes

Chemical Communications, Journal Year: 2024, Volume and Issue: 60(27), P. 3717 - 3720

Published: Jan. 1, 2024

The substrate-enabled switching of the regioselectivity allows for efficient regiocontrol via [4+1] and [3+2] annulations ninhydrin-derived MBH carbonates with α,β-unsaturated ketones to access highly substituted furans cyclopentene.

Language: Английский

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Lewis Base Controlled (4 + 3) and (4 + 2) Annulations of MBH Carbonates with Benzofuran‐derived Azadienes: Access to Highly Substituted Benzofuro[3,2‐b]azepines and Spirotetrahydroquinolines

Advanced Synthesis & Catalysis, Journal Year: 2024, Volume and Issue: 366(21), P. 4521 - 4527

Published: Aug. 7, 2024

Abstract Catalyst‐controlled switchable (4+3) and (4+2) annulation reactions of Morita–Baylis–Hillman carbonates with benzofuran‐derived azadienes have been established. Employing PCy 3 as the catalyst, reaction could provide a variety synthetically useful benzofuro[3,2‐ b ]azepines in good yields (80–92%) excellent chemo‐ regioselectivities via cycloaddition reactions. Whereas changing catalyst from to DMAP, were switched construct highly substituted spirotetrahydroquinoline scaffolds three sequential stereocenters containing all‐carbon spiro‐quaternary efficiency diastereoselectivities (92–96% all cases>25:1 dr ) annulations. In addition, synthetic utility this method was further showcased by gram‐scale transformations product.

Language: Английский

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Phosphine-Catalyzed Cascade Cycloaddition of Vinyl Oxiranes with Sulfonium Compounds to Step-Economically Construct Spiro-2(3H)-furanone Scaffolds

Organic Letters, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 9, 2025

In this work, we developed a phosphine-catalyzed cascade lactonization/[2 + 1] annulation reaction between vinyl oxiranes and sulfonium compounds for the highly diastereoselective construction of spiro-2(3H)-furanone skeletons. The cycloaddition proceeds via 2(5H)-furanone phosphonium intermediate, introducing an oxygen-containing active intermediate phosphine catalysis. These findings highlight significant potential harnessing as versatile synthons constructing spirocyclic through simultaneous multicyclic skeleton formation.

Language: Английский

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Synthesis of polysubstituted spiroazepines via [4 + 3] annulation reaction of ninhydrin-derived Morita−Baylis−Hillman carbonates with 1‑heterodienes

Journal of Molecular Structure, Journal Year: 2025, Volume and Issue: unknown, P. 141478 - 141478

Published: Jan. 1, 2025

Language: Английский

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Aqueous/Nonaqueous DBU Mixtures: Versatile Switching Media for Chemoselective Aldol, Baylis‐Hillman, and Aldol Condensation Reactions

ChemistryOpen, Journal Year: 2025, Volume and Issue: unknown

Published: March 20, 2025

Abstract Isophorone is a relatively small molecule with several neighboring reacting sites, making it susceptible to various competing reactions aldehydes, including aldol, Baylis‐Hillman (BH), aldol condensation, and Michael addition reactions. In the present work, we have designed switchable 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU)‐catalyzed procedure, where reaction of isophorone aldehydes guided chemoselectively toward either BH, or condensation reactions, depending on use water and/or heat. This controllable divergency likely stems from ability tune dual nucleophilicity/basicity characters DBU/H 2 O medium. other words, nucleophilicity DBU plays crucial role in directing process formation BH adducts absence water. At same time, pathway dominates when present. The conditions were amenable for tandem processes, as demonstrated an condensation/Diels‐Alder sequence.

Language: Английский

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[3 + 2] Cycloaddition of quinazoline-derived azomethine imines with electron-deficient alkenes to access functionalized fused tricyclic tetrahydropyrazolo[1,5-c]quinazoline frameworks

Tetrahedron, Journal Year: 2025, Volume and Issue: unknown, P. 134749 - 134749

Published: May 1, 2025

Language: Английский

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Substrate-Controlled Diversity-Oriented Synthesis of Novel Polycyclic Frameworks via [4 + 2] and [3 + 2] Annulations of Ninhydrin-Derived MBH Adducts with 3,4-Dihydroisoquinolines

Molecules, Journal Year: 2023, Volume and Issue: 28(19), P. 6761 - 6761

Published: Sept. 22, 2023

Substrate-controlled diversity-oriented synthesis of polycyclic frameworks via [4 + 2] and [3 annulations between ninhydrin-derived Morita-Baylis-Hillman (MBH) adducts 3,4-dihydroisoquinolines under similar reaction conditions have been developed. The provides a series novel structurally complex spiro multi heterocyclic skeletons in good yields (up to 87% 90%, respectively) with excellent diastereoselectivities >25:1 dr). In particular, the switchable annulation reactions are controlled by tuning hydroxyl protecting group on MBH adduct deliver structural diverse spiro[indene-2,2'-[1,3]oxazino[2,3-a]isoquinoline] spiro[indene-2,1'-pyrrolo[2,1-a]isoquinoline], respectively. Furthermore, relative configuration chemical structure two kinds cycloadducts were confirmed through X-ray diffraction analysis.

Language: Английский

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DMAP Catalyzed Ring-Opening/Cycloaddition of Vinyl Oxiranes with Activated Ketone Compounds to Construct the 1,3-Dioxolane Skeletons

Organic Letters, Journal Year: 2024, Volume and Issue: 26(43), P. 9322 - 9327

Published: Oct. 24, 2024

The present work develops a DMAP-catalyzed [3 + 2] cycloaddition of vinyl oxiranes with activated ketone compounds, affording dioxolane derivatives moderate to excellent yields. This approach represents the first Lewis base (LB)-catalyzed ring-opening reaction epoxides, simultaneously providing rare oxygen-containing active intermediate in this field. gram-scale preparation and facile derivatization cycloadduct highlight significant synthetic potential strategy.

Language: Английский

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Synthesis of functionalized spiro[indanone-benzazepine] scaffolds via [4 + 3] annulation reaction of N-(o-chloromethyl)aryl amides with ninhydrin-derived Morita−Baylis−Hillman carbonates

Tetrahedron, Journal Year: 2023, Volume and Issue: 150, P. 133772 - 133772

Published: Dec. 1, 2023

Language: Английский

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