Facile Synthesis of Polysubstituted 2-Pyrones via TfOH-Mediated Ring Expansion of 2-Acylcyclopropane-1-carboxylates

Abstract

A facile route to polysubstituted 2-pyrones from readily available 2-acylcyclopropane-1-aryl-1-carboxylates mediated by TfOH is reported. The strongly donating 1-aryl group is important for directing the C-C bond cleavage of the donor-acceptor cyclopropane ring, which then leads to the formation of the 2-pyrone ring through lactonization.

Metal-catalyzed reactions of organic nitriles and boronic acids to access diverse functionality

“…58 Inspired by this method, in 2021, Yu and Zhang's group also reported a similar three-component reaction for the synthesis of 4-arylquinazolines ( 123 ) via a Pd( ii )-catalyzed cascade reaction of 2-aminobenzonitriles ( 122 ), arylboronic acid, and triethyl orthocarboxylate instead of aldehydes (Scheme 61). 84 This method involves C(sp)–C(sp 2 ) coupling followed by intramolecular C−N bond formation via the Pd( ii ) catalyst. In addition, this transformation has been applied for the synthesis of a highly potent bioactive compound, translocator protein (TSPO) ligand.…”

Fluoroalkylated hypervalent sulfur fluorides: radical addition of arylchlorotetrafluoro-λ6-sulfanes to tetrafluoroethylene

“…2 Therefore, researchers have explored various applications of this moiety and dedicated substantial efforts to developing effective synthetic methods for compounds containing the SF 5 group. 2–7 Initial direct fluorination methods require strong oxidants, leading to low yields and poor functional group tolerance because of side reactions, such as overfluorination or C–C/C–S fragmentation. 3 However, recent advancements in the synthesis of aliphatic compounds with the SF 5 group have been achieved through the rapid development of synthetic methods using SF 5 X reagents, expanding the accessible range.…”

“…8 A notable breakthrough in the synthesis of ArSF 5 has been the development of two-step routes via arylchlorotetrafluoro-λ 6 -sulfanes (ArSF 4 Cl) (Scheme 1A, left). 5,6 These methods have enabled the scalable and inexpensive synthesis of ArSF 5 compounds by using less expensive and milder oxidants, such as Cl 2 and trichloroisocyanuric acid (TCICA).…”

Synthesis of vinyl-1,2,3-triazole derivatives under transition metal-free conditions

“…1,2,3-Triazole compounds are an important class of nitrogen-containing heterocyclic compounds that are often introduced into existing drugs or lead compounds as pharmacodynamic groups to improve their pharmacological activity. 1,2 In addition, their derivatives have a variety of biological activities, such as antibacterial, 3 anti-malaria, 4 anti-HIV, 5 anti-fungal, 6 anticancer 7 and anti-inflammatory, 8 activities ( Fig. 1 ), which are indispensable in the field of new drug research and development.…”