Enantioselective (3+2) Annulation of Donor‐Acceptor Cyclopropanes with Aldehydes and Ketones Catalyzed by Brønsted Bases DOI Creative Commons
Erlaitz Basabe Obregón, Louise G. Rost, Ida R. Kocemba

et al.

Angewandte Chemie, Journal Year: 2024, Volume and Issue: 136(42)

Published: July 15, 2024

Abstract The substituted tetrahydrofuran core is a structural motif in many biologically active and natural compounds. However, the scarcity of enantioselective methods developed towards its synthesis makes this field challenging attractive to explore. Herein, first Brønsted‐base catalyzed (3+2) annulation donor‐acceptor cyclopropanes with aldehydes ketones affording enantioenriched 2,3,5‐substituted tetrahydrofurans reported. reaction concept based on activation racemic β‐cyclopropyl by chiral bifunctional Brønsted base which catalyzes for range ketones. For aldehydes, furnished excellent yield, good diastereoselectivity enantioselectivity up >99 % ee . Surprisingly, aromatic afforded cis ‐2,5‐substituted as major diastereoisomer, while aliphatic trans ‐cycloadduct was favored. also proceeds well spiro yields enantioselectivities (up 99 ). Hammett studies have been conducted elucidate influence electronic nature benzaldehydes stereoselectivity. Based diastereochemical outcome two paths are proposed. Finally, diastereoselective synthetic transformations demonstrate potential obtained products.

Language: Английский

Lewis Acid-Enabled Chemodivergent Cycloadditions of Donor–Acceptor Cyclopropanes with Indoline-2-Thiones DOI

Chen-Ying Zhai,

Bing Zhao, Xuelong Wang

et al.

The Journal of Organic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 20, 2025

Lewis acid-enabled reactions of donor-acceptor cyclopropanes (DACs) with indoline-2-thiones are reported. The reaction exhibits tunable annulation depending on the acid and substituent at N1 indoline-2-thiones. With AlCl3 as 1-isopropylindoline-2-thiones reactants, a direct ring opening DACs, followed by intramolecular nucleophilic addition/dehydration takes place leading to formation dihydro-2H-thiepino[2,3-b]indoles in moderate good yields. Using Yb(OTf)3 promoter 1-unsubstituted (3 + 2) cycloaddition DACs accompanied sulfur rearrangement give 3-indolyl-4,5-dihydrothiophenes In addition, synthetic transformation 3-indolyl-4,5-dihydrothiophene sulfone indole-based axially chiral scaffolds further extends utility structural complexity.

Language: Английский

Citations

1
Enantioselective (3+2) Annulation of Donor‐Acceptor Cyclopropanes with Aldehydes and Ketones Catalyzed by Brønsted Bases DOI Creative Commons
Erlaitz Basabe Obregón, Louise G. Rost, Ida R. Kocemba

et al.

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: unknown

Published: July 15, 2024

Abstract The substituted tetrahydrofuran core is a structural motif in many biologically active and natural compounds. However, the scarcity of enantioselective methods developed towards its synthesis makes this field challenging attractive to explore. Herein, first Brønsted‐base catalyzed (3+2) annulation donor‐acceptor cyclopropanes with aldehydes ketones affording enantioenriched 2,3,5‐substituted tetrahydrofurans reported. reaction concept based on activation racemic β‐cyclopropyl by chiral bifunctional Brønsted base which catalyzes for range ketones. For aldehydes, furnished excellent yield, good diastereoselectivity enantioselectivity up >99 % ee . Surprisingly, aromatic afforded cis ‐2,5‐substituted as major diastereoisomer, while aliphatic trans ‐cycloadduct was favored. also proceeds well spiro yields enantioselectivities (up 99 ). Hammett studies have been conducted elucidate influence electronic nature benzaldehydes stereoselectivity. Based diastereochemical outcome two paths are proposed. Finally, diastereoselective synthetic transformations demonstrate potential obtained products.

Language: Английский

Citations

6
Transition-metal-free regioselective synthesis of spiro-oxazolidines through [3 + 2] annulation reactions of azadienes with haloalcohols DOI Creative Commons

Amol T. Savekar,

Sonali M. Vitnor,

Vishal B. Karande

et al.

RSC Advances, Journal Year: 2025, Volume and Issue: 15(14), P. 10634 - 10638

Published: Jan. 1, 2025

The transition-metal-free regioselective [3 + 2] annulation of azadienes with haloalcohols for the preparation highly functionalized spiro-oxazolidines is experimentally simple, broad substrate scope, good yields, and excellent regioselectivity.

Language: Английский

Citations

0
Phosphine-catalyzed [3 + 2]-annulation of Morita–Baylis–Hillman carbonates with benzofuran-derived azadienes: Synthesis of spiro-cyclopentane benzofurans DOI

Wanxing Liu,

Yandong Lv,

Xiaohang Liu

et al.

Tetrahedron, Journal Year: 2025, Volume and Issue: 182, P. 134703 - 134703

Published: May 9, 2025

Language: Английский

Citations

0
Enantioselective (3+2) Annulation of Donor‐Acceptor Cyclopropanes with Aldehydes and Ketones Catalyzed by Brønsted Bases DOI Creative Commons
Erlaitz Basabe Obregón, Louise G. Rost, Ida R. Kocemba

et al.

Angewandte Chemie, Journal Year: 2024, Volume and Issue: 136(42)

Published: July 15, 2024

Abstract The substituted tetrahydrofuran core is a structural motif in many biologically active and natural compounds. However, the scarcity of enantioselective methods developed towards its synthesis makes this field challenging attractive to explore. Herein, first Brønsted‐base catalyzed (3+2) annulation donor‐acceptor cyclopropanes with aldehydes ketones affording enantioenriched 2,3,5‐substituted tetrahydrofurans reported. reaction concept based on activation racemic β‐cyclopropyl by chiral bifunctional Brønsted base which catalyzes for range ketones. For aldehydes, furnished excellent yield, good diastereoselectivity enantioselectivity up >99 % ee . Surprisingly, aromatic afforded cis ‐2,5‐substituted as major diastereoisomer, while aliphatic trans ‐cycloadduct was favored. also proceeds well spiro yields enantioselectivities (up 99 ). Hammett studies have been conducted elucidate influence electronic nature benzaldehydes stereoselectivity. Based diastereochemical outcome two paths are proposed. Finally, diastereoselective synthetic transformations demonstrate potential obtained products.

Language: Английский

Citations

0