A Luminescent Stable Triarylmethyl Diradical with an Axially Chiral Spacer

Chemistry - A European Journal, Journal Year: 2025, Volume and Issue: unknown

Published: March 6, 2025

Two units of a highly stable luminescent triarylmethyl radical (PyBTM) were bridged using chiral octahydrobinaphthyl moiety, resulting in diradical with sufficient stability to enable the measurement its chiroptical properties. To synthesize this diradical, novel boronic ester precursor, αH-PyBTM-B(Epin), was designed. The use precursor significantly improved yield and streamlined preparation radical-substituted molecules. photoluminescence quantum (PLQY) measured be 10 % chloroform. Furthermore, both circular dichroism (CD) circularly polarized luminescence (CPL) successfully observed.

Language: Английский

---

Access to Chiral Bridged Biaryls via Brønsted Acid-Catalyzed Asymmetric Addition of Alcohols to Fluoroalkylated Biaryl Oxazepines

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

Published: Jan. 24, 2025

We disclose herein a chiral phosphoric-acid-catalyzed enantioselective addition reaction of alcohols to fluoroalkylated biaryl 1,3-oxoazepines, which furnished wide range bridged biaryls bearing quaternary carbon stereocenter on the seven-membered ring in high yields (up 99%) with excellent enantioselectivities 98% ee). Our method can be used for modification several natural products and bioactive molecules. Preliminary studies revealed that obtained this exhibit good vitro bioactivities against two plant pathogens.

Language: Английский

---

Kinetic Resolution of Amino Acids by Phosphine Oxide Catalyzed Enantioselective Esterification

Research Square (Research Square), Journal Year: 2025, Volume and Issue: unknown

Published: May 7, 2025

The first highly efficient kinetic resolution (KR) of racemic amino acids with L-pyroglutaminol as an esterification reagent was reported through a novel phosphine oxide organocatalyst catalyzed under mild conditions, which provides wide range chiral esters and recovered excellent stereoselectivities (s > 1057). catalyst demonstrated stereocontrol catalytic activity, presumably benefited from intimate double H-bonding interaction between the pyroglutaminol core catalyst. Chiral find applications versatile building blocks in synthesis functional molecules, source information asymmetric tools to expand explore function native biological machinery.^1–8 Therefore, represent class valuable indispensable compounds whose stereoselective is major objective within synthetic chemists biologists.^9–10 To best our knowledge, array effective strategies for construction have been developed, such hydrogenation nucleophilic addition imines^11–18, enantioselective carbene insertion into N-H bonds amines or amides^19–23, photobiocatalytic cross-coupling^24–27, stereocontrolled 1,3-nitrogen migration carboxylic acids²⁸. However, identifying specific reaction not always easy task. An alternative well-established strategy relies on KR mixture (Fig. 1a).^29–31 stands out one most practical straightforward obtaining enantioenriched molecules recovering starting materials, effectively allowing access both enantiomers single enantiomer Numerous processes developed that reliably deliver enantiopure compounds, including alcohols^32–36, monohydrosilanes³⁷, organoperoxides³⁸, alkynes^39–40, sulfonyl ketones⁴¹, amines⁴², imines⁴³, sulfoximines^44–45, aldehydes⁴⁶, phosphindane oxides^47–48, heterocyclic compounds^49–52. Despite this significant progress field, remains challenging task has rarely explored.^53–57

Language: Английский

---

Bridged Biaryl Atropisomers by Organocatalyzed Kinetic Asymmetric Alcoholysis

Organic Letters, Journal Year: 2024, Volume and Issue: 26(34), P. 7110 - 7115

Published: Aug. 16, 2024

We disclose herein an asymmetric synthesis of axially chiral oxazepine-containing bridged biaryls via CPA-catalyzed kinetic alcoholysis. Control experiments showed that this alcoholysis was reversible, and lowering the reaction temperature could almost suppress reversible reaction, thus providing a series biaryl compounds in good to excellent enantioselectivities. The gram-scale reactions facile derivatizations enantioenriched products demonstrate practical utility reaction.

Language: Английский

---