Desulfonylation of aryl alkyl sulfones

Trost, Barry M.; Arndt, Henry C.; Strege, Paul E.; Verhoeven, Thomas R.

doi:10.1016/s0040-4039(00)71334-7

Cited by 303 publications

(86 citation statements)

References 5 publications

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“…The final step in our synthesis was achieved by hydrogenolysis of the sulphone moiety with 6% sodium amalgam in a method analogous to that of Trost et al (18). Once again some difficulties were encountered in this reaction due to the steric hindrance of functionalities attached to the carbon cr, to the ring.…”

mentioning

confidence: 99%

Synthesis of (±)-trixagol by an electrophilic cyclization of an allylsilane

Armstrong¹,

Weiler²

1983

Can. J. Chem.

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confidence: 99%

Synthesis of (±)-trixagol by an electrophilic cyclization of an allylsilane

Armstrong¹,

Weiler²

1983

Can. J. Chem.

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“…After stirring for 6 hr, the mixture was neutralized by adding Et3N until litmus paper indicated the basic condition. The mixture was poured into H2O (50 ml) and extracted with AcOEt (30 ml×4 (17). A suspension of 16 (103 mg, 335 mmol) and 10z Pd W C (15.5 mg) in methanol (2.0 ml) was vigorously stirred at room temperature under an H2 atmosphere for 10 hr.…”

Section: (E )-4-[2-(tert-butyldimethylsilyloxy)-5-(methoxymethoxy) Phmentioning

confidence: 99%

“…16,17) The addition of a THF solution of crude aldehyde 21 at "789 C to the solution of a lithio-sulfone, which had been generated by butyllithium from 25, introduced a coupling reaction to aŠord adduct 22 in an 81z yield as a mixture of four possible diastereomers. These were subjected to the next step without separation.…”

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confidence: 99%

Total Synthesis of Both Enantiomers of Dictyochromenol and their (Z)-Isomers

Aoki

Takahashi

Hashimoto

et al. 2002

Bioscience, Biotechnology, and Biochemistry

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“…Dissolving metal reductions using sodium amalgam (15,21,26), or Li or Ca (21) in liquid ammonia, are other reductive cleavage reagents. Since carboxylates are known to be relatively resistant to dissolving metal reductions, the tetraacid 17 was chosen as the starting material.…”

Section: Ligand Synthesismentioning

confidence: 99%

Polycarboxylate diaza crown ethers derived from R,R-(+)-tartaric acid: synthesis and complexation of metal ions

Anantanarayan¹,

Fyles²

1990

Can. J. Chem.

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ASHOK ANANTANARAYAN and THOMAS M. FYLES. Can. J. Chem. 68, 1338 (1990.The synthesis and complexation properties of polycarboxylate diaza crown ethers based on R,R-(+)-tartaric acid are described. Cesium carbonate mediated macrocyclization of a bis-tosylamide precursor with a bis-tosylate precursor provided the protected crown ethers. Photochemical deprotection of the tosylamides and hydrolysis of the carboxamides yielded dicarboxylic and tetracarboxylic acid derivatives of 1, lO-diaza-18-crown-6. N-Methylenecarboxylate (N-acetate) derivatives were prepared by N-alkylation with bromoacetic acid. The synthetic and purification procedures developed provide samples of the ligands in a metal-free form. Acidity and stability constants for complexation of alkali metal, alkaline earth, late-and post-transition metal cations were determined by potentiometric titration. The ligands form complexes which show enhancement of stability by charge-charge and chelate interaction with the carboxylates. In comparison with crown ether polycarboxylates these aza crown ethers showed a selectivity for softer metal ions relative to alkali and alkaline earth metal ions. N-Methylenecarboxylate chelate ligands were found to bind almost all types of metal ions, due to a highly co-operative array of charge-charge, chelate and crown ether interactions. Metal ion recognition by synthetic and naturally occurring ligands is a complex process involving a cooperative match of the complementary properties of the host and the guest. A key factor in the design of new ligands with unique complexation behaviors is the choice of ligand donor sites (1). Within a class of ligands, such as the crown ethers or cryptands, clear changes in selectivity of cation binding are provoked by substitution of the oxygen donors of a parent ring system for nitrogen or sulfur donor sites (2). Such substitutions alter the primary character of the donor (Lewis basicity) as well as the geometrical and conformational properties of the ligand (3). Thus in a system involving highly cooperative binding interactions, donor atom substitution can profoundly influence binding selectivity.Our interest in ligand design has centered on crown ethers derived from R,R-(+)-tartaric acid: the di-, tetra-, and hexaacids illustrated at the top of Fig. 1 (4-6). The tartarate derived units impart rigidity to the ligands, leading to well defined conformations, and the carboxylates, when ionized, provide a strong electrostatic field which greatly enhances complex stability for alkali metal and alkaline earth cations. Despite the favorable Coulombic interactions, binding of heavy metal cations occurs only to a limited extent due to a mismatch of the hard oxygen donor set and the softer guest cations (6). An obvious ligand modification which might lead to stabilized crown ether type complexes of heavier cations would be the substitution of some of the donor atoms for N or S. We have previously reported dithia crown ethers bearing four carboxylates (7); the purpose of this report is to describe th...

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Desulfonylation of aryl alkyl sulfones

Cited by 303 publications

References 5 publications

Synthesis of (±)-trixagol by an electrophilic cyclization of an allylsilane

Synthesis of (±)-trixagol by an electrophilic cyclization of an allylsilane

Total Synthesis of Both Enantiomers of Dictyochromenol and their (Z)-Isomers

Polycarboxylate diaza crown ethers derived from R,R-(+)-tartaric acid: synthesis and complexation of metal ions

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