Novel strategy for the synthesis of chiral pseudo-ortho-substituted hydroxy[2.2]paracyclophane-based ligands from the resolved 4-bromo-12-hydroxy[2.2]paracyclophane as a parent compound

Zhuravsky, R. P.; Starikova, Z. A.; Воронцов, Е. В.; Rozenberg, V. I.

doi:10.1016/j.tetasy.2007.12.010

Cited by 45 publications

(20 citation statements)

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“…Thereafter, dibromide rac-14 was converted into bromo alcohol rac-15, which was resolved through the separation of the diastereomeric esters of (1S)-camphanic acid. [16] Diastereomeric esters (1S,R P )-16 and (1S,S P )-16 were obtained as white crystalline solids in 49 and 44 % yield, respectively, after column chromatography (Scheme 2). As depicted in Figure 3, the (1S,R P )-16 diastereomer was crystallized and subjected to X-ray crystalstructure analysis.…”

Section: Resultsmentioning

confidence: 99%

Planar‐Chiral Thioureas as Hydrogen‐Bond Catalysts

et al. 2010

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confidence: 99%

Planar‐Chiral Thioureas as Hydrogen‐Bond Catalysts

et al. 2010

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“…For the synthesis of the phosphoric acid diester, we started from enantiopure ( S P )‐4‐bromo‐12‐hydroxy[2.2]paracyclophane (( S P )‐ 20 ) which can be synthesized in five steps from [2.2]paracyclophane ( 5 ), involving a resolution employing the diastereomeric ester with (1 S )‐(−)‐camphanic acid (Scheme ). The resolution has been described previously by Rozenberg and coworkers 27…”

Section: Resultsmentioning

confidence: 99%

“…A Suzuki coupling of enantiopure ( S P )‐ 20 with 2‐hydroxyphenyl boronic acid ( 21 ) gave the diol ( S P )‐ 22 in 70% yield (Scheme ). This compound has been mentioned in the literature several times,27–29 but no characterization has been published so far.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and application of the first planar chiral strong brønsted acid organocatalysts

Enders¹,

Ludwig²,

Raabe³

2012

Chirality

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The synthesis of planar chiral strong Brønsted acid organocatalysts derived from [2.2]paracyclophane is described. Resolution was accomplished according to a modified protocol involving pseudo-ortho-substituted [2.2]paracyclophane-based sulfoxides for the synthesis of three new sulfonic acids. The first planar chiral phosphoric acid diester was obtained from the corresponding phenyl-substituted diol derived from enantiopure 4-bromo-12-hydroxy [2.2]paracyclophane. These new classes of catalysts were tested in an enantioselective Friedel-Crafts reaction as well as in a direct asymmetric Mannich reaction and gave yields of up to 93% and ee-values of up to 38%.

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“…Triflation of the pseudoortho-bromo[2.2]paracyclophanol 3, which is readily available in an enantiopure form, would set the stage for the stepwise successive palladium-catalyzed installation of two functional groups, that is, the polar functionality (R 1 ) to directly connect to the backbone and an aryl group equipped with the second functionality (R 2 ). The different leaving groups (Br and OTf) in 4 might make it easier to 19 was triflated by conventional means (Scheme 2), and the palladium-catalyzed amination of the obtained (S p )-4 was investigated. As a result, a two-step procedure, which consists of the Buchwald-Hartwig amination using N-tert-butyl carbamate as the ammonia equivalent 20 and subsequent exposure to trifluoroacetic acid, was found to selectively give the desired mono-aminated cyclophanyl triflate (S p )-5 in good yield.…”

Section: Resultsmentioning

confidence: 99%