Enantioselective Catalytic Cyclopropanation–Rearrangement Approach to Chiral Spiroketals

Organic Letters, Год журнала: 2021, Номер 23(10), С. 3955 - 3959

Опубликована: Май 6, 2021

A highly enantioselective synthesis of chiral heterobicyclic spiroketals is reported via a "one-pot" cyclopropanation–rearrangement (CP-RA) cascade reaction that sequentially catalyzed by Rh(II) catalyst and tetrabutylammonium fluoride (TBAF). Exocyclic vinyl substrates form spirocyclopropanes with tert-butyldimethylsilyl-protected enoldiazoacetates in excellent yields enantioselectivities when dirhodium(II) carboxylates, following desilylation simultaneous rearrangement the presence TBAF, they give (S)-spiroketals high chirality retention (>95% ee).

Язык: Английский

---

Side arm modified chiral bisoxazoline ligands: Recent development and prospect in asymmetric catalysis

Tetrahedron, Год журнала: 2022, Номер 129, С. 133121 - 133121

Опубликована: Окт. 31, 2022

Язык: Английский

---

Copper‐Catalyzed Asymmetric Diyne Cyclization via [1,2]‐Stevens‐Type Rearrangement for the Synthesis of Chiral Chromeno[3,4‐c]pyrroles

Angewandte Chemie, Год журнала: 2021, Номер 134(7)

Опубликована: Дек. 14, 2021

Abstract Here, we report a copper‐catalyzed asymmetric cascade cyclization/[1,2]‐Stevens‐type rearrangement via non‐diazo approach, leading to the practical and atom‐economic assembly of various valuable chiral chromeno[3,4‐ c ]pyrroles bearing quaternary carbon stereocenter in generally moderate good yields with wide substrate scope excellent enantioselectivities (up 99 % ee). Importantly, this protocol not only represents first example catalytic [1,2]‐Stevens‐type based on alkynes but also constitutes formal carbene insertion into Si−O bond .

Язык: Английский

---

Strategies and Methods for the Catalytic Asymmetric Synthesis of Benzofuran/Benzopyran Fused Acetals: A Review

Advanced Synthesis & Catalysis, Год журнала: 2023, Номер 365(24), С. 4320 - 4333

Опубликована: Ноя. 17, 2023

Benzofuran- and benzopyran-fused polycyclic acetals are found in a variety of biologically active natural products. The synthetic methods toward this class heterocycles have fascinated one the most intensive pursuits total synthesis. Nevertheless, stereoselective towards rapid construction such skeletons still remain challenging for organic chemists. Significant progress has been made research area recent years, however, literature on enantioselective approaches to construct these molecules not fully reviewed. Driven by their intriguing complex scaffolds with potential usefulness, we compose advances review covering all important works field. We hope will promote future area.

Язык: Английский

---

Ruthenium-Catalyzed Intramolecular Double Hydrofunctionalization of Alkynes. Synthesis of Spirocyclic Hemiaminal Ethers and Their Lewis Acid-Mediated Cleavage/Nucleophilic Addition

The Journal of Organic Chemistry, Год журнала: 2021, Номер 86(9), С. 6674 - 6697

Опубликована: Апрель 16, 2021

[RuCl2(p-cymene)]2/AgNO3-catalyzed intramolecular double hydrofunctionalization of internal alkynes having nitrogen and oxygen nucleophilic groups at appropriate positions provided a series spirocyclic hemiaminal ether derivatives in good to excellent yields. The product spiro-hemiaminal ethers underwent Lewis acid-mediated chemoselective cleavage, situ-generated iminium/oxocarbenium ions could be trapped with nucleophiles afford range heterocycles.

Язык: Английский

---

Stereodivergent Synthesis of Spiroaminals via Chiral Bifunctional Hydrogen Bonding Organocatalysis

Angewandte Chemie, Год журнала: 2024, Номер unknown

Опубликована: Апрель 2, 2024

Abstract Spiroaminals represent novel structural motifs prevalent in diverse natural products and biologically active molecules. Achieving their enantioselective synthesis is a highly desirable challenging task synthetic endeavors due to intricate molecular frameworks. Herein, we accomplished the first stereodivergent construction of spiroaminals using chiral bifunctional organocatalyzed intramolecular 1,2‐addition followed by an oxa‐Michael addition cascade high atom step economical pathway. A proper modulation cinchona‐derived squaramide catalysts efficiently provided access all possible stereoisomers with yield, diastereoselectivity, excellent enantioselectivity while displaying broad substrate tolerance. Additionally, validated scalability reaction demonstrated variable spiroaminal scaffolds, confirming viability our protocol.

Язык: Английский

---

Copper Catalyzed [3+2] Annulation Reaction of Exocyclic Sulfonyl Enamides for the Synthesis of N,O‐Spiroketal and Spiroketal

Chemistry - A European Journal, Год журнала: 2024, Номер 30(44)

Опубликована: Июнь 1, 2024

A copper-catalyzed [3+2] annulation reaction of exocyclic enamines/enol ethers with 1,4-benzoquinone esters has been developed, providing facile access to N,O-spiroketals and spiroketals under mild conditions broad substrate scope (26 examples, 71-94 % yields). Gram scale synthesis chemical transformations demonstrated that this method is potentially useful in the natural products drugs containing a N,O- spiroketal moiety. The chiral N,O-spiroketal could be obtained 98 ee after recrystallization, when SaBOX ligand was employed.

Язык: Английский

---

Enantioselective Synthesis of Spiroketals and Spiroaminals via Gold and Iridium Sequential Catalysis

Angewandte Chemie, Год журнала: 2022, Номер 134(26)

Опубликована: Апрель 21, 2022

Abstract The enantioselective cascade reaction between racemic 2‐(1‐hydroxyallyl)phenols and alkynols/alkynamides was realized by using a gold iridium sequential catalytic system. In this procedure, the in situ generated exocyclic vinyl ethers or enamides undergo asymmetric allylation/spiroketalization with π‐ally‐Ir amphiphilic species, which provides an efficient straightforward access to spiroketals spiroaminals excellent enantioselectivities. Moreover, 2‐(1‐hydroxyallyl)anilines were also suitable along kinetic resolution process, affording enantioenriched good yields. synthetic utility of method has been demonstrated synthesis analogue Paecilospirone.

Язык: Английский

---

Asymmetric syntheses of spiro[benzofuro-cyclopenta[1,2-b]indole–indoline] scaffolds via consecutive cyclization

Chemical Communications, Год журнала: 2021, Номер 57(18), С. 2313 - 2316

Опубликована: Янв. 1, 2021

Highly diastereo- and enantioselective spiro[benzofuro-cyclopenta[1,2-b]indole–indoline] scaffolds with five successive stereogenic centers two spiroheterocycles were synthesized via consecutive cyclization.

Язык: Английский

---

Cu(II)-Catalyzed Synthesis of 4-(1,4,5,6-Tetrahydropyridin-3-yl)-1,4-dihydroisoquinolin-3-ones from 4-Diazoisoquinolin-3-ones

The Journal of Organic Chemistry, Год журнала: 2022, Номер 87(6), С. 4088 - 4096

Опубликована: Фев. 25, 2022

We report a simple, efficient, and highly selective C-H bond insertion of copper carbenes generated in situ from 4-diazo-1,4-dihydroisoquinolin-3-ones into β-C(sp2)-H bonds N-sulfonyl enamides, which gave series 4-(1,4,5,6-tetrahydropyridin-3-yl)-1,4-dihydroisoquinolin-3(2H)-ones good to excellent yields. Operationally simple mild reaction conditions, cheap catalyst, readily accessible starting materials, broad substrate scope are the merits this reaction.

Язык: Английский

---