Cerium(III) Chloride-Mediated Reactions of Sulfonamide Dianions

Johnson, David C.; Widlanski, Theodore S.

doi:10.1021/jo034001w

Cited by 24 publications

(15 citation statements)

References 86 publications

(122 reference statements)

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“…Compounds 3aa ,8f 3ab ,8f 3ac ,12 3ad ,13 3ae ,8f 3ba ,14 3be ,8f,9d 3da ,8a,15 3dd ,8a,16 3ea ,17 3eb ,18 3ed ,18 3ee ,9b 3fa ,19 3ga ,15 3ha ,20 and 3ia 21 had been reported previously, and their identities were confirmed by comparison of their melting points and spectroscopic data with the reported data. Characterization data for the new compounds 3bb , 3bc , 3bd , 3ca , 3cb , and 3cd are shown below.…”

Section: Methodssupporting

confidence: 80%

Phosphotungstic Acid Catalyzed Amidation of Alcohols

Wang

Shen

2008

Eur J Org Chem

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Mild nucleophilic substitution reactions of benzhydrylic, benzylic, allylic, and simple aliphatic alcohols with sulfonamides, benzamide, and 4‐nitroaniline in the presence of 12‐phosphotungstic acid as an efficient, eco‐friendly, cheap, and air‐ and moisture‐tolerant catalyst for the construction of C–N bonds has been investigated. The amine derivatives were obtained in good yields (up to 98 %). The reusable nature of the 12‐phosphotungstic acid makes this protocol more attractive.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

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Section: Methodssupporting

confidence: 80%

Phosphotungstic Acid Catalyzed Amidation of Alcohols

Wang

Shen

2008

Eur J Org Chem

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“…Further useful dianions can be generated from ketones (C=C(OM)CM or C=C(OM)CCM) [138][139][140][141][142], carboxylic acids (C=C(OM) 2 ) [143][144][145], succinic acid derivatives ((C=C(OM)OR) 2 ) [146], alkynes (MC"CCM, MC"CC-OM) [147][148][149][150][151][152][153][154][155], imidazoles [156], thiophenes [157,158], b-alanine derivatives (MN-CC=C(OM)X) [159], 3-nitropropanoates [160,161], 3-hydroxypropanoates [162,163], 2-hydroxyethylsulfones [164,165], arenes [166][167][168], allenes [169], thioamides [170], and sulfonamides (MC-SO 2 NM [171]; R 2 NSO 2 -CM 2 [172]). If the nucleophilic sites in the polyanion have different chemical hardness, regioselective alkylation can be achieved by selecting a soft or a hard electrophile (second reaction, Scheme 5.13).…”

Section: 36mentioning

confidence: 99%

“…Typical pK a values of hydrocarbons and some compounds with carbon-heteroatom single bonds are given in Table 5.2. Li, Na, K to Mg, Mn, Cu, Zn, Cd, Ce, In, Ti, or Zr) will be required to reduce the basicity of the carbanion [171,[182][183][184][185][186][187][188]. Instead of forming a bond with an electrophile, these strongly basic carbanions can also just deprotonate it if the electrophile can act as an acid.…”

Section: A-heteroatom Carbanionsmentioning

confidence: 99%

The Alkylation of Carbanions

Dörwald

2004

Side Reactions in Organic Synthesis

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The deprotonation of organic compounds by strong, non-nucleophilic bases followed by C-alkylation with a suitable electrophile has become one of the most predictable and straightforward methods for formation of C-C bonds. The popularity of this chemistry is also a consequence of the often-seen close resemblance of feasible structural modifications by a deprotonation/alkylation strategy to an unsophisticated retrosynthetic analysis of a given target compound. Other reactions, which involve, for instance, substantial rearrangement of the carbon framework (e.g. Cope rearrangement, fragmentations, ring contractions or enlargements) are usually more difficult to take into account during retrosynthetic analysis.LDA and related, sterically hindered, lithium dialkylamides, first investigated by Levine [1], have completely replaced the more nucleophilic sodium amide, which had been the base of choice for many years [2]. Because the reactivity of an organometallic compound depends to a large extent on its state of aggregation (i.e. on the solvent and on additives) and on the metal, transmetalation of the lithiated intermediates and the choice of different solvents and additives emerged as powerful strategies for fine-tuning the reactivity of these valuable nucleophiles.In this chapter the alkylation of carbanions with simple carbon electrophiles will be discussed, with special emphasis on the structure-reactivity relationship of the carbanion and on side reactions. In this context the term "carbanion" refers to an intermediate prepared by in-situ deprotonation of an organic compound, followed by optional cation exchange (transmetalation), which tends to be alkylated at carbon by soft electrophiles such as MeI or PhCHO. This type of reactivity is characteristic of enolates with an ionic M-O bond or for organometallic compounds with a strongly polarized or ionic M-C bond, M typically being an alkali metal, Mg, Cu, or Zn. Carbanions can, alternatively, also be prepared by halogen-metal exchange [3-8], sulfoxide-or sulfone-metal exchange [9-13], or by transmetalation of stannanes. The most suitable reagents for performing such metalating exchange reactions are organometallic compounds with a metal-bound secondary or tertiary alkyl group, such as tBuLi, sBuLi, iPr 2 Zn [14, 15], or iPrMgHal [6]. These reagents are thermodynamically less stable than organometallic compounds with primary alkyl 5 146 Scheme 5.1. Approximate relative rates of proton transfer in water at thermoneutrality (DpK a = 0) [35, 39, 51]. 147 Scheme 5.2. The effect of fluorine on the acidity of organic compounds [24, 62-65]. 148 Scheme 5.3. Dependence of the reactivity of carbanions on their basicity [68, 72-74]. Regioselectivity of Deprotonations and AlkylationsThe organic chemist is occasionally confronted with the problem that a compound has several differrent X-H groups of similar pK a . If only one of these is to be alkylated, one option would be to perform a regioselective deprotonation. This can sometimes be achieved by exploiting small differences be...

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“…The sulfonyl and sulfonamide groups are known to improve the water solubility of target compounds by their ability to form hydrogen bonds, and can be used to fine tune the p K a values of the amino groups due to their strong inductive effect 2. As a result, the research on pharmaceutical precursors that bear a sulfonyl or a sulfonamide group has been a focal issue in the study of synthetic drugs 3. For instance, flavocristamide A ( 1 ) is a naturally occurring sulfonolipid which efficiently inhibits the enzyme DNA polymerase A 4.…”

Section: Introductionmentioning

confidence: 99%

Synergetic Catalytic Effects in Tri‐Component Mesostructured Ru–Cu–Ce Oxide Nanocomposite in CO Oxidation

Cui¹,

Wang²,

Chen³

et al. 2014

ChemCatChem

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This work focuses on probing the synergetic catalytic effects in mesostructured tri‐component Ru–Cu–Ce oxides in CO oxidation reaction. The crystallized nanocomposites with RuO2 and CuO nanoparticles dispersed homogeneously in the pore network of mesoporous CeO2 were synthesized by the nanocasting replication method. The greatly enhanced catalytic activity was achieved by CuO incorporating in mesoporous CeO2, and further by RuO2 incorporating in the mesostructure of CuO/CeO2. Two types of synergetic catalytic mechanisms have been preliminarily proposed to be copresent in the system: CeO2 activation by CuO through generating oxygen vacancies at CeO2/CuO interface and the CeO2 surface nearby, which consequently activate the oxygen species (O*) and enhance the CO oxidation activity of the bi‐metal CuCe oxide, and the simultaneous adsorption of CO molecules and their activation in parallel on the active surface of RuO2, which results in further elevated catalytic activity.

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Cerium(III) Chloride-Mediated Reactions of Sulfonamide Dianions

Cited by 24 publications

References 86 publications

Phosphotungstic Acid Catalyzed Amidation of Alcohols

Phosphotungstic Acid Catalyzed Amidation of Alcohols

The Alkylation of Carbanions

Synergetic Catalytic Effects in Tri‐Component Mesostructured Ru–Cu–Ce Oxide Nanocomposite in CO Oxidation

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