Chiral Gold Complex Catalyzed Cycloisomerization/Regio- and Enantioselective Nitroso-Diels–Alder Reaction of 1,6-Diyne Esters with Nitrosobenzenes

ACS Catalysis, Год журнала: 2022, Номер 12(12), С. 7288 - 7299

Опубликована: Июнь 3, 2022

An efficient chiral gold(I) complex-catalyzed synthetic method that enables the cycloisomerization/regio- and enantioselective nitroso-Diels–Alder (NDA) reaction of 1,6-diyne esters with nitrosobenzenes is described. The sequential ring formation protocol offers access to a wide variety 3,5,6,8a-tetrahydro-1H-benzo[c][1,2]oxazines as single regioisomer in yields up 99% enantiomeric excess values 99%. This contrast analogous NDA reactions cycloisomerized ester nitrosoarenes absence complex catalytic system, which were found give N,O-heterocyclic product opposite regiochemistry. Experimental computational studies based on postulated dinuclear gold species containing two coordinated nitrosoarene molecules undergoes an asynchronous concerted provides insight into observed regio- enantioselectivities.

Язык: Английский

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I₂‐Catalyzed Cycloisomerization of Ynamides: Chemoselective and Divergent Access to Indole Derivatives

Angewandte Chemie International Edition, Год журнала: 2022, Номер 62(8)

Опубликована: Дек. 27, 2022

Herein, an I2 -catalyzed unprecedented cycloisomerization of ynamides is developed, furnishing various functionalized bis(indole) derivatives in generally good to excellent yields with wide substrate scope and atom-economy. This protocol not only represents the first molecular-iodine-catalyzed tandem complex alkyne cycloisomerizations, but also constitutes chemoselective tryptamine-ynamides involving distinctively different C(sp3 )-C(sp3 ) bond cleavage rearrangement. Moreover, chiral tetrahydropyridine frameworks containing two stereocenters are obtained moderate diastereoselectivities enantioselectivities. Meanwhile, aromatization produce pyrrolyl indoles high efficiency enabled by . Additionally, control experiments theoretical calculations reveal that this reaction probably undergoes a 5-exo-dig cyclization/rearrangement process.

Язык: Английский

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Cyclization reactions in confined space

Current Opinion in Colloid & Interface Science, Год журнала: 2023, Номер 64, С. 101680 - 101680

Опубликована: Фев. 14, 2023

Cyclization of chain substrates into ring products is an important reaction in organic synthesis. The ease this process measured by the Effective Molarity, which indicates that some rings (5, 6 and 7-membered ones) are especially facile to close, while others (>8 membered) far more challenging. Confinement cyclization inside nanometric cavity capsules, coordination cages or porous materials can greatly facilitate via preorganization reagents stabilization transition states, also offering chance alter innate selectivity reaction. Moreover, use chiral cavities enables control over stereoselectivity. Eventually, pre-organization substrate closure medium large rings, a longstanding goal This review analyzes examples nanoconfinement improve reactions, their close challenging rings.

Язык: Английский

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Hydrogen-Bonded Matched Ion Pair Gold(I) Catalysis

ACS Catalysis, Год журнала: 2023, Номер 13(15), С. 10217 - 10223

Опубликована: Июль 20, 2023

The enantioselective reaction of 1,6-enynes with O-, N-, and C-nucleophiles has been developed by matched ion pair gold(I) catalysis in which the chiral cation anion are H-bonded through a urea group. Very high levels enantiocontrol achieved (up to >99:1 er) for broad scope substrates. DFT studies demonstrate importance H-bond donor group anchoring cation- anion-favoring additional noncovalent interactions.

Язык: Английский

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Recent advances with calix[6]- and calix[8]arene organometallic catalysts

Tetrahedron Letters, Год журнала: 2022, Номер 112, С. 154221 - 154221

Опубликована: Окт. 31, 2022

Язык: Английский

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