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Meroterpenoids isolated from fungi of the Ganoderma family have received much attention owing to their unique structures and diverse biological activities. A number of Ganoderma meroterpenoids have been isolated since 2000 and many total syntheses and synthetic studies have since been reported. In this review, we highlight fifteen total syntheses conducted from 2014 to 2023 of polycyclic Ganoderma meroterpenoids classified according to the connection pattern of the dihydroquinone with the terpenoid structure. The selected studies illustrate how the molecular complexity was constructed by unique tactics. [ABSTRACT FROM AUTHOR]

An efficient tosylhydrazine-mediated conjugate reduction of 3-phenacylideneoxindole and sequential Michael/intramolecular aldol reaction is reported under base-catalyzed conditions towards the formation of densely substituted dispirocyclopentanebisoxindole derivatives. The reaction proceeded in a diastereoselective manner to afford four chiral stereocenters. The method also has advantages of wide substrate scope, readily available starting materials and operational simplicity through one pot reaction.

A simple and efficient method for α-brominating lactones that affords α-bromolactones under mild conditions using tetraalkylammonium hydroxide (R4N+OH−) as a base was developed. Lactones are ring-opened with Br2 and a substoichiometric amount of PBr3, leading to good yields of the corresponding α-bromocarboxylic acids. Subsequent intramolecular cyclization over 1 h using a two-phase system (H2O/CHCl3) containing R4N+OH− afforded α-bromo lactones in good yields. This method can be applied at the 10 mmol scale using simple operations. α-Bromo-δ-valerolactone, which is extremely reactive and difficult to isolate, could be isolated and stored in a freezer for about one week using the developed method. Optimizing the solvent for environmentally friendly large-scale syntheses revealed that methyl ethyl ketone (MEK) was as effective. In addition, in situ-generated α-bromo-δ-valerolactone was directly converted into a sulfur-substituted functional lactone without difficulty by reacting it with a sulfur nucleophile in one pot without isolation. This new bromination system is expected to facilitate the industrial use of α-bromolactones as important intermediates.

A sequential one‐pot method for the synthesis of 4‐(hydroxymethyl)oxazoles from readily available benzamides has been developed. Various substituted benzamides well‐tolerated and furnished 4‐(hydroxymethyl)oxazoles in moderate to good yields under the present reaction conditions. In order to demonstrate the usefulness of the present methodology, the resulting 4‐(hydroxymethyl)oxazoles were successfully transformed into its corresponding phosphonates under Michaelis‐Arbuzov reaction conditions. This methodology features a broad substrate scope, step economy, ease of execution, and scalability. [ABSTRACT FROM AUTHOR]

A series of compounds containing the benzoxazepine-isoquinoline scaffold was synthesized in a one-pot procedure via an Ugi reaction followed by tautomerization reaction between the keto and enol forms and intramolecular nucleophilic substitution. The microwave-assisted strategy allowed the facile synthesis of a library of target compounds and is applicable to the construction of diverse libraries of related compounds for high throughput screening in medicinal chemistry. [ABSTRACT FROM AUTHOR]

An efficient tosylhydrazine-mediated conjugate reduction of 3-phenacylideneoxindole and sequential Michael/intramolecular aldol reaction is reported under base-catalyzed conditions towards the formation of densely substituted dispirocyclopentanebisoxindole derivatives. The reaction proceeded in a diastereoselective manner to afford four chiral stereocenters. The method also has advantages of wide substrate scope, readily available starting materials and operational simplicity through one pot reaction., (Copyright © 2022, Pramanik and Mukhopadhyay.)

A simple and efficient method for α-brominating lactones that affords α - bromolactones under mild conditions using tetraalkylammonium hydroxide (R 4 N + OH - ) as a base was developed. Lactones are ring-opened with Br 2 and a substoichiometric amount of PBr 3 , leading to good yields of the corresponding α-bromocarboxylic acids. Subsequent intramolecular cyclization over 1 h using a two-phase system (H 2 O/CHCl 3 ) containing R 4 N + OH - afforded α-bromo lactones in good yields. This method can be applied at the 10 mmol scale using simple operations. α-Bromo-δ-valerolactone, which is extremely reactive and difficult to isolate, could be isolated and stored in a freezer for about one week using the developed method. Optimizing the solvent for environmentally friendly large-scale syntheses revealed that methyl ethyl ketone (MEK) was as effective. In addition, in situ-generated α-bromo-δ-valerolactone was directly converted into a sulfur-substituted functional lactone without difficulty by reacting it with a sulfur nucleophile in one pot without isolation. This new bromination system is expected to facilitate the industrial use of α-bromolactones as important intermediates., (Copyright © 2021, Yamamoto et al.)

Abstract: A series of fused benzimidazole–quinoxalinones were synthesized utilizing a one-pot UDC (Ugi/de-protection/cyclization) strategy to form a benzimidazole group with subsequent intermolecular nucleophilic substitution reaction to form quinoxalinone functionality. Using combinations of either a tethered ketone acid or aldehyde acid input the Ugi reaction was shown to afford (1) a ring system through lactamization, (2) a benzimidazole through de-protection and cyclization, and (3) a quinoxalinone through the nucleophilic substitution reaction. Scaffolds were produced in good yields and facile operation. [Copyright &y& Elsevier]

Manganese dioxide is often used as a curing agent for polysulfide polymers because of its excellent properties. Here, we synthesize a freshly ordered macroporous MnO2 with crystalline framework walls using a handy method called one-pot operation. It is worth noting that this synthesis approach of the ordered macroporous MnO2 is facile and simple. It can obviously improve the mechanical properties of polysulfide polymers and accelerate the rate of vulcanization. [ABSTRACT FROM AUTHOR]