4-Bromo-2-sulfolenes. Butadienyl cation equivalents

Chou, Ta Shue; Hung, Su Chun; Tso, Hsi-Hwa

doi:10.1021/jo00391a042

Cited by 45 publications

(22 citation statements)

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“…In 1987, T.-S. Chou and co-workers explored the use of 4-bromo-2-sulfolene (11) as a useful building block for the synthesis of a variety of mono-substituted 2-sulfolene and 3-sulfolene species through reaction with a range of nucleophiles (Scheme 8). 30 Alkylcuprates were found to react at the C2 position, resulting in 2-alkyl-3-sulfolene products 26a and 26b. Phenyl-or allylcuprates reacted directly at the C4 position, displacing the bromine atom to form 2-sulfolene products 27a and 27b.…”

Section: Sulfolenes Through Nucleophilic Addition To 4-bromo-2-sulfolenementioning

confidence: 99%

“…Phenyl-or allylcuprates reacted directly at the C4 position, displacing the bromine atom to form 2-sulfolene products 27a and 27b. 30 Fruitful double-bond isomerization of 27a and 27b to the 3-sulfolene isomers 28a and 28b, respectively, was accomplished using triethylamine in quantitative yield. 30 Strongly basic nucleophiles such as organolithium or Grignard reagents were found to abstract the C5 hydrogen, causing the deprotonation/elimination reaction to occur.…”

Section: Sulfolenes Through Nucleophilic Addition To 4-bromo-2-sulfolenementioning

confidence: 99%

“…30 Fruitful double-bond isomerization of 27a and 27b to the 3-sulfolene isomers 28a and 28b, respectively, was accomplished using triethylamine in quantitative yield. 30 Strongly basic nucleophiles such as organolithium or Grignard reagents were found to abstract the C5 hydrogen, causing the deprotonation/elimination reaction to occur. 30 The highly unstable intermediate 29 subsequently dimerizes and extrudes sulfur dioxide to form bicyclic sulfone 30.…”

Section: Sulfolenes Through Nucleophilic Addition To 4-bromo-2-sulfolenementioning

confidence: 99%

“…30 Strongly basic nucleophiles such as organolithium or Grignard reagents were found to abstract the C5 hydrogen, causing the deprotonation/elimination reaction to occur. 30 The highly unstable intermediate 29 subsequently dimerizes and extrudes sulfur dioxide to form bicyclic sulfone 30. Reaction with sodium phenylsulfinate was found to afford the 3-sulfolene 31 in an 86% yield.…”

Section: Sulfolenes Through Nucleophilic Addition To 4-bromo-2-sulfolenementioning

confidence: 99%

“…Reaction with sodium phenylsulfinate was found to afford the 3-sulfolene 31 in an 86% yield. 30 Treatment of 11 with sodium nitrite provided 4-hydroxy-2sulfolene (32) (15%:18%:13%:6%)…”

Section: Sulfolenes Through Nucleophilic Addition To 4-bromo-2-sulfolenementioning

confidence: 99%

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3-Sulfolenes and Their Derivatives: Synthesis and Applications

Brant

Wulff

2015

Synthesis

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The diverse substitution patterns available to 3-sulfolenes have long made them useful for the preparation of multi-substituted 1,3-diene equivalents. More recently, the 3-sulfolene motif itself (or its reduced sulfolane congener) is finding increasing application as a structural element in the creation of molecules for biological applications. This review describes various methods to afford 3-sulfolene building blocks and their derivatives. Selected applications in synthetic and medicinal chemistry are also discussed. 1 Introduction 2 The Preparation of Monocyclic Sulfolene Building Blocks 2.1 Sulfolenes through Electrophilic Addition 2.1.1 Sulfolenes through Nucleophilic Addition to 4-Bromo-2-sulfolene 2.2 Sulfolenes through Oxidation of a Thiol Precursor 2.3 Sulfolenes through Noble Metal Catalysis 2.4 Sulfolenes through Deprotonation Followed by Alkylation 3 Synthesis of Bicyclic Sulfolenes and Their Derivatives 3.

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Section: Sulfolenes Through Nucleophilic Addition To 4-bromo-2-sulfolenementioning

confidence: 99%

Section: Sulfolenes Through Nucleophilic Addition To 4-bromo-2-sulfolenementioning

confidence: 99%

Section: Sulfolenes Through Nucleophilic Addition To 4-bromo-2-sulfolenementioning

confidence: 99%

Section: Sulfolenes Through Nucleophilic Addition To 4-bromo-2-sulfolenementioning

confidence: 99%

“…Reaction with sodium phenylsulfinate was found to afford the 3-sulfolene 31 in an 86% yield. 30 Treatment of 11 with sodium nitrite provided 4-hydroxy-2sulfolene (32) (15%:18%:13%:6%)…”

Section: Sulfolenes Through Nucleophilic Addition To 4-bromo-2-sulfolenementioning

confidence: 99%

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3-Sulfolenes and Their Derivatives: Synthesis and Applications

Brant

Wulff

2015

Synthesis

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Organocopper Reagents: Substitution, Conjugate Addition, Carbo/Metallocupration, and Other Reactions

1992

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Well over a decade ago, two reviews were contributed to the Organic Reactions series covering substitution and conjugate addition reactions in organocopper chemistry. Their appearance, which highlighted most of the early work in this field, served not only as a source of invaluable references to original literature reports, but also stimulated a vast number of subsequent studies on the properties and uses of organocopper complexes. The work cited in this chapter, which dates from ca. 1975, concerns in large measure uses of organocopper complexes originating from either catalytic or stoichiometric quantities of a copper(I) halide together with a Grignard (RMgX) or organolithium (RLi) reagent. These combinations form either neutral organocopper reagents RCu ( 1 ) or copper(I) monoanionic salts R 2 CuM (M = Li or MgX), commonly referred to as “lower‐order” species. The latter ate complexes with lithium as gegenion ( 2 ) are also known as “Gilman reagents” in recognition of their origins. Copper(I) cyanide is also an excellent precursor, affording homogeneous mixtures of lower order cyanocuprates RCu(CN)Li, ( 3 ), upon treatment with an equivalent of an organolithium. The strength of the CuCN linkage presumably accounts for direct cuprate formation with 1 equivalent of the organolithium, rather than the metathesis that occurs with copper(I) chloride, bromide, or iodide. While use of reagents ( 1 ), ( 2 ) and ( 3 ) alone can be aptly classified as broad‐based and intense, their importance has further encouraged extensive development of variations on these themes (i.e., their composition and reactivity profiles). Reagents ( 1–3 ) have been found to be unexpectedly compatible with certain electrophilic additives at low temperatures, which substantially alter their reactivity. Rather than forming ( 2 ) from 2 equivalents of the same RLi, different organolithiums can be utilized to give R T R R CuLi, ( 4 ), conserving potentially valuable RLi. This scenario raises the question of controlling the selectivity of transfer of the desired ligand R T rather than the anticipated residual (or “dummy”) group R R from copper to electrophilic carbon. Fortunately, many solutions to this problem now exist. Admixture of 2RLi (or R T Li + R R Li) with copper(I) cyanide proceeds beyond the stage of ( 3 ) to ultimately arrive at copper(I) dianionic complexes 5 , the so‐called “higher‐order” cyanocuprates. Undoubtedly it is the cyano ligand, with its π‐acidic nature, which enables copper to accept a third negatively charged ligand. Although reagents ( 5 ) do not yet share in all of the benefits offered by time in comparison with their lower‐order counterparts, they nicely complement prior art. Moreover, as with species ( 1–4 ), they continue to evolve, providing the synthetic community with alternatives for highly selective and efficient means of making key carbon–carbon bonds.

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Extrusion Reactions Affording Aromatic Systems, Dienes and Polyenes

Guziec

2022

Organic Reactions

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Extrusion reactions may be defined as chemical reactions in which an atom or small molecular fragment Y connected to two other atoms W and Z is lost from a molecule, leading to a product in which W becomes directly bonded to Z. Cheletropic reactions that afford aromatic or conjugated π systems by loss of a stable atomic or molecular fragment have also been classified as extrusion reactions. Typically, the fragments liberated in these reactions are small, stable inorganic molecules or atoms such as carbon monoxide, carbon dioxide, sulfur, sulfur monoxide, sulfur dioxide, selenium, tellurium, oxygen and nitrogen. This chapter primarily deals with the synthesis of arenes, heterocycles, 1,3‐dienes and polyenes using such extrusion processes. The utility of these reactions in the synthesis of sterically hindered molecules, dendrimers, pheromones, and other natural products are highlighted. The use of extrusion reactions for the “Click and Release” approach in drug development is also introduced.

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4-Bromo-2-sulfolenes. Butadienyl cation equivalents

Cited by 45 publications

References 0 publications

3-Sulfolenes and Their Derivatives: Synthesis and Applications

3-Sulfolenes and Their Derivatives: Synthesis and Applications

Organocopper Reagents: Substitution, Conjugate Addition, Carbo/Metallocupration, and Other Reactions

Extrusion Reactions Affording Aromatic Systems, Dienes and Polyenes

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