Asymmetric [3 + 2] cycloaddition of donor–acceptor cyclopropanes with azadienes enabled by Brønsted base catalysis

Organic Chemistry Frontiers, Год журнала: 2024, Номер 11(10), С. 2905 - 2910

Опубликована: Янв. 1, 2024

A chiral bifunctional Brønsted base-catalyzed enantioselective [3 + 2] cycloaddition of D–A cyclopropanes and azadienes is reported. The protocol features broad substrate scope, mild reaction conditions high functional group tolerance.

Язык: Английский

---

Combining palladium and ammonium halide catalysts for Morita–Baylis–Hillman carbonates of methyl vinyl ketone: from 1,4-carbodipoles to ion pairs

Chemical Science, Год журнала: 2021, Номер 12(34), С. 11399 - 11405

Опубликована: Янв. 1, 2021

Here we report that Morita-Baylis-Hillman carbonates from diverse aldehydes and methyl vinyl ketones can be directly utilised as palladium-trimethylenemethane 1,4-carbodipole-type precursors, both reactivity enantioselectivity are finely regulated by adding a chiral ammonium halide the ion-pair catalyst. The newly assembled intermediates, proposed to contain an electronically neutral π-allylpalladium complex reactive compact ion pair, efficiently undergo asymmetric [4 + 2] annulations with activated alkenes or isatins, generally high regio-, diastereo- enantio-selectivity, even switchable regiodivergent diastereodivergent well realised tuning substrate catalyst assemblies. An array of control experiments, including UV/Vis absorption study density functional theory calculations, conducted rationalise this new double activation mode combining palladium

Язык: Английский

---

Vinylcyclopropanes as All-Carbon 1,5-Dipoles: A Reactivity Switch for Palladium-Catalyzed (5 + 4) Cycloadditions

Organic Letters, Год журнала: 2021, Номер 23(6), С. 2332 - 2336

Опубликована: Март 4, 2021

Azonanes were prepared by a palladium-catalyzed (5 + 4) cycloaddition between activated vinylcyclopropanes and 1-azadienes. During this process, the vinylcyclopropane partner displayed an unusual reactivity behaved as all-carbon 1,5-dipole. A N,N-bidentate ligand was required to inhibit formation of thermodynamic (3 2) cycloadducts.

Язык: Английский

---

Ligand-Controlled Regiodivergent Asymmetric [5 + 2] and [3 + 2] Annulations of Vinyl Indoloxazolidones Catalyzed by Palladium

Organic Letters, Год журнала: 2021, Номер 23(12), С. 4791 - 4795

Опубликована: Июнь 9, 2021

Here, we present palladium-catalyzed regiodivergent asymmetric annulations of vinyl indoloxazolidones, which can act as 1,5-carbodipoles or 1,3-carbodipoles by tuning the chiral ligands and conditions, in assemblies with sulfamate-derived cyclic imines even activated alkenes. A diversity polycyclic products are generally constructed high regio- enantioselectivity.

Язык: Английский

---

Phosphine-Catalyzed (4 + 2) Annulation of Allenoates with Benzofuran-Derived Azadienes and Subsequent Thio-Michael Addition

Organic Letters, Год журнала: 2022, Номер 24(20), С. 3747 - 3752

Опубликована: Май 13, 2022

A phosphine-catalyzed (4 + 2) annulation of tetrahydrobenzofuranone-derived allenoates and benzofuran-derived azadienes (BDAs) has been achieved to construct the decahydro-2H-naphtho[1,8-bc]furan derivatives, which were subsequently treated with 4-methylbenzenethiol trimethylamine produce thio-Michael addition products in high excellent yields good diastereoselectivities.

Язык: Английский

---