Desaromatisierungsstrategien in der Synthese strukturell komplexer Naturstoffe

Roche, Stéphane; Porco, John A.

doi:10.1002/ange.201006017

Cited by 327 publications

(28 citation statements)

References 264 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…[23] The previously reported compound bisA C H T U N G T R E N N U N G (allyl)calcium (1) [24] undergoes rapid 1,2-insertion of pyridine and subsequent rearrangement to give the 1,4-carbometalated product (Scheme 1). [25] By this procedure, an allyl moiety can easily be attached to the C 5 H 5 N ring, without the need for an activating or protecting group.…”

Section: Introductionmentioning

confidence: 98%

Calcium‐Mediated Dearomatization, CH Bond Activation, and Allylation of Alkylated and Benzannulated Pyridine Derivatives

Jochmann

Leich

Spaniol

et al. 2011

Chemistry A European J

View full text Add to dashboard Cite

A facile and general synthetic pathway for the production of dearomatized, allylated, and C-H bond activated pyridine derivatives is presented. Reaction of the corresponding derivative with the previously reported reagent bis(allyl)calcium, [Ca(C(3)H(5))(2)] (1), cleanly affords the product in high yield. The range of N-heterocyclic compounds studied comprised 2-picoline (2), 4-picoline (3), 2,6-lutidine (4), 4-tert-butylpyridine (5), 2,2'-bipyridine (6), acridine (7), quinoline (8), and isoquinoline (9). Depending on the substitution pattern of the pyridine derivative, either carbometalation or C-H bond activation products are obtained. In the absence of methyl groups ortho or para to the nitrogen atom, carbometalation leads to dearomatized products. C(sp(3))-H bond activation occurs at ortho and para situated methyl groups. Steric shielding of the 4-position in pyridine yields the ring-metalated product through C(sp(2))-H bond activation instead. The isolated compounds [Ca(2-CH(2)-C(5)H(4)N)(2)(THF)] (2b⋅(THF)), [Ca(4-CH(2)-C(5)H(4)N)(2)(THF)(2)] (3b⋅(THF)(2)), [Ca(2-CH(2)-C(5)H(3)N-6-CH(3))(2)(THF)(n)] (4b⋅(THF)(n); n=0, 0.75), [Ca{2-C(5)H(3)N-4-C(CH(3))(3)}(2)(THF)(2)] (5c⋅(THF)(2)), [Ca{4,4'-(C(3)H(5))(2)-(C(10)H(8)N(2))}(THF)] (6a⋅(THF)), [Ca(NC(13) H(9)-9-C(3)H(5))(2)(THF)] (7a⋅(THF)), [Ca(4-C(3) H(5)-C(9) H(7)N)(2)(THF)] (8b⋅(THF)), and [Ca(1-C(3)H(5)-C(9)H(7) N)(2)(THF)(3)] (9a⋅(THF)(3)) have been characterized by NMR spectroscopy and metal analysis. 9a⋅(THF)(4) and 4b⋅(THF)(3) were additionally characterized in the solid state by X-ray diffraction experiments. 4b⋅(THF)(3) shows an aza-allyl coordination mode in the solid state. Based on the results, mechanistic aspects are discussed in the context of previous findings.

show abstract

Section: Introductionmentioning

confidence: 98%

Calcium‐Mediated Dearomatization, CH Bond Activation, and Allylation of Alkylated and Benzannulated Pyridine Derivatives

Jochmann

Leich

Spaniol

et al. 2011

Chemistry A European J

View full text Add to dashboard Cite

show abstract

“…[21] As detailed in Figure 3 d, different substrates, including tetrahydrocarbazoles, reacted with 2 a or phenacyl bromides to afford products 4 a-f bearing a quaternary stereocenter. [21] As detailed in Figure 3 d, different substrates, including tetrahydrocarbazoles, reacted with 2 a or phenacyl bromides to afford products 4 a-f bearing a quaternary stereocenter.…”

mentioning

confidence: 99%

X‐Ray Characterization of an Electron Donor–Acceptor Complex that Drives the Photochemical Alkylation of Indoles

et al. 2014

View full text Add to dashboard Cite

A metal-free, photochemical strategy for the direct alkylation of indoles was developed. The reaction, which occurs at ambient temperature, is driven by the photochemical activity of electron donor-acceptor (EDA) complexes, generated upon association of substituted 1H-indoles with electron-accepting benzyl and phenacyl bromides. Significant mechanistic insights are provided by the X-ray single-crystal analysis of an EDA complex relevant to the photoalkylation and the determination of the quantum yield (Φ) of the process.

show abstract

“…[19] The reduction steps are believed to take place via the 3-keto tautomers of 2 and 4. [27,28] However, dearomatization reactions concurrent with asymmetric catalysis in one step are very challenging. [15] The two reductases are members of the short-chain dehydrogenase/ reductase (SDR) family.…”

mentioning

confidence: 99%

Tetrahydroxynaphthalene Reductase: Catalytic Properties of an Enzyme Involved in Reductive Asymmetric Naphthol Dearomatization

et al. 2012

View full text Add to dashboard Cite

In reduced circumstances: tetrahydroxynaphthalene reductase shows a broad substrate range including alternate phenolic compounds and cyclic ketones. Structural modeling reveals major enzyme-substrate interactions; C-terminal truncation of the enzyme causes an altered substrate preference, in accordance with stabilization of the substrate by the C-terminal carboxylate. This effect allows the identification of a homologous enzyme.

show abstract

Desaromatisierungsstrategien in der Synthese strukturell komplexer Naturstoffe

Cited by 327 publications

References 264 publications

Calcium‐Mediated Dearomatization, CH Bond Activation, and Allylation of Alkylated and Benzannulated Pyridine Derivatives

Calcium‐Mediated Dearomatization, CH Bond Activation, and Allylation of Alkylated and Benzannulated Pyridine Derivatives

X‐Ray Characterization of an Electron Donor–Acceptor Complex that Drives the Photochemical Alkylation of Indoles

Tetrahydroxynaphthalene Reductase: Catalytic Properties of an Enzyme Involved in Reductive Asymmetric Naphthol Dearomatization

Contact Info

Product

Resources

About