Gram-Scale Synthesis of 3-Sulfonyl Flavanones

Tandem C- and O-alkylative annulation of β-ketosulfones with 1,2-bisbromomethyl arenes: one-pot construction of sulfonyl indanes and dioxadibenzofused macrocycles

Herein, a tandem synthetic route for constructing sulfonyl indanes and dioxadibenzofused macrocycles is described. This strategy involves a transition-metal-free, base-mediated tandem C- and O-alkylative annulation of β-ketosulfones with 1,2-bisbromomethyl arenes with moderate to excellent yields under open-vessel reaction conditions. In the overall reaction process, two carbon-carbon (C-C) and two carbon-oxygen (C-O) bonds are formed. Various base-promoted reaction conditions are screened for this one-pot easy-to-operate conversion.

Sequential condensation and double desulfonylative cyclopropanation of 1,2-bis(sulfonylmethyl)arenes with 3-arylacroleins: access to biscyclopropane-fused tetralins

Efficient tBuOK-mediated sequential condensation and double desulfonylative cyclopropanation of readily accessible 1,2-bis(sulfonylmethyl)arenes with 3-arylacroleins is described. This high-yielding, single-step strategy provides a variety of polysubstituted biscyclopropane-fused tetralins with six contiguous stereogenic centers via the construction of five carbon-carbon single bonds. A plausible mechanism is proposed and discussed. In the overall reaction process, water and sulfinic acid salts were generated as the byproducts.

BF3·OEt2-mediated nucleophilic fluorocyclization of sulfonyl 3-methylene-oxabenzocyclooctan-6-ones. Diastereocontrolled synthesis of benzofused fluorooxabicyclo[4.2.1]nonanes

We describe a facile-operational, high-yield method for the diastereocontrolled preparation of novel sulfonyl benzofused fluorooxabicyclo[4.2.1]nonanes by a straightforward synthetic route, including (i) NaBH₄-mediated reduction of sulfonyl 3-methylene-oxabenzocyclooctan-6-ones and (ii) BF₃·OEt₂-mediated intramolecular nucleophilic fluorocyclization. The plausible mechanism for the preparation is proposed and discussed. This protocol can easily install a fluoro-atom on the bridged head position in a short time and under mild conditions, resulting in one carbon-carbon and one carbon-fluorine bond formation.

Recent advances in the synthesis and applications of β-keto sulfones: new prospects for the synthesis of β-keto thiosulfones

This review mainly focuses on recent developments in the preparation of β-keto sulfones and their extensive synthetic applications. New prospects for the synthesis of β-keto thiosulfones have also been highlighted. Over the last decade, there has been exponential growth in the direct construction of β-keto sulfones using a wide variety of keto and sulfonyl precursors. Of note, the most promising photoredox transformations and electrochemical synthesis methods of β-keto sulfones are also presented. Moreover, β-keto sulfones are versatile building blocks in organic synthesis due to their three essential functional groups: sulfonyl, carbonyl, and active methylene moieties. The convenient preparation of β-keto sulfones allows the synthesis of many valuable carbocyclic and heterocyclic compounds, and the effortless removal of the sulfonyl moiety via transformations is supported. The chemistry of β-keto sulfones (2013 to present) can be divided into several sections based on the sulfonyl surrogates, and ubiquitous synthetic strategies were systematically outlined.