Synthesis of five-membered homothiosugars derived from l-erythrose and d-mannose

Copper(I)‐Promoted Synthesis of Highly Substituted and Functionalized Tetrahydrothiophenes

“…The synthesis of dihydrothiophenes by dehydroacetoxylation of such derivatives has also been reported . A THT ring bearing a functionalized side‐chain is an important intermediate in the synthesis of many drug candidates , . The presence of a β‐halogen group in a THT ring increases its synthetic utility for further substitution, elimination/aromatization reactions,[20a], [20b], and selective dehalogenation .…”

“…Thus, some complex β‐substituted THTs, pharmaceutically important compounds, and natural products have been synthesized . However, there is a scarcity of mild, short,, and straightforward[16a], methods for the introduction of an α‐acetoxy group into a THT ring, or for the introduction of various other functionalities into the side‐chain that may be sensitive to even slightly acidic or basicreaction conditions, and thus require neutral reaction conditions for their installation. The introduction of a halogen atom at the β (C) position of a tetrahydrothiophene ring is challenging.…”

“…The synthesis of functionalized THTs by substitution reactions of acyclic precursors with chlorine or bromine and/or acetoxy substituents already installed, using Na 2 S, NaSH, organic sulfides etc., is a common approach. [1b], [19b], However, such reactions are not suitable for the synthesis of β‐halo and α‐acetoxy THTs, or THTs containing other sensitive groups, due to the possibility of elimination, substitution, and other side reactions at these centres , , . On the other hand, radical cyclization is considered to be a mild and neutral method for the synthesis of carbo‐ and heterocycles, taking place under neutral reaction conditions, and with a high degree of functional group tolerance.…”

1-Hydroxymethyl-4-phenylsulfonybutadiene, a Versatile Building Block for the Synthesis of 2,3,4-Trisusbtituted Tetrahydrothiophenes

“…The most common procedure for the synthesis of thiosugars, is based on the introduction of a thiol group by a double nucleophilic replacement of sulfonyloxy groups in the required positions. Other polyhydroxylated chiral thiolanes have been obtained by introduction the thiol group by conjugate addition, followed by internal displacement of a sulfonyloxy group [7]. This tandem reaction has been used by us in the synthesis of pyrrolidines such as 5 [4].…”

Deoxythiosugar Derivatives with Furano, Pyrano, and Septano Motifs from L‐Gulono‐1,4‐lactone and D‐Glycero‐D‐gulo‐heptono‐1,4‐lactone

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A short synthesis of thiosugar derivatives mimicking furanose, pyranose, and septanose structures has been achieved starting from L-gulono-1,4-lactone and D-glucoheptono-1,4lactone. [8] However, a more general and efficient synthesis of thiosugars from carbohydrates is required in contemporary organic synthesis. All of these reactions used benzyltriethylammonium tetrathiomolybdate, (BnEt 3 N) 2 MoS 4 as the sulfur-transfer reagent.

thioacetals, [6] nucleophilic double displacement using sulfur nucleophiles, [7] and conjugate addition of sulfur nucleophiles to unsaturated esters followed by tandem cyclization.

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