Enantioselektive Addition von Allyltrimethoxysilanen an Aldehyde mitp-Tol-BINAP⋅AgF als Katalysator

Yanagisawa, Akira; Kageyama, Hiromi; Nakatsuka, Yoshinari; Asakawa, Kenichi; Matsumoto, Yoshihisa; Yamamoto, Hisashi

doi:10.1002/(sici)1521-3757(19991216)111:24<3916::aid-ange3916>3.0.co;2-v

Cited by 31 publications

(1 citation statement)

References 39 publications

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“…Our group reported the first example of asymmetric silver‐catalyzed addition of allyltrimethoxysilanes to aldehydes 5. Recently we have demonstrated that these conditions can be successfully applied to a highly diastereo‐ and enantioselective allylation of ketones 6.…”

Section: Resultsmentioning

confidence: 99%

Enantioselective Ag‐Catalyzed Allylation of Aldimines

2009

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A highly enantioselective synthesis of homoallylic amines, using allyltrimethoxysilane under AgI catalytic conditions, has been developed. Among the chiral ligands investigated, a remarkable difference in the resulting AgI complexes was observed. Under mild conditions and low catalyst loadings, homoallylamines were produced in high ee values (up to 80%) and good yields. The methodology can be further extended to a diastere- and enantioselective crotylation of aldimines.

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Section: Resultsmentioning

confidence: 99%

Enantioselective Ag‐Catalyzed Allylation of Aldimines

2009

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Asymmetric 1,4‐Addition of Organoboron Reagents to Quinone Monoketals Catalyzed by a Chiral Diene/Rhodium Complex: A New Synthetic Route to Enantioenriched 2‐Aryltetralones

Tokunaga

Hayashi

2007

Adv Synth Catal

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A novel synthetic approach to 2-aryltetralones with high ee has been developed through asymmetric 1,4-addition of arylboronic acids to naphthoquinone monoketals catalyzed by a rhodium complex with the (R,R)-Ph-bod* ligand. The asymmetric addition proceeded in high yields with excellent enantioselectivity.Keywords: asymmetric catalysis; boron; chiral diene ligands; conjugate addition; quinone monoketals; rhodium Enantiomerically pure carbonyl compounds bearing aryl or alkenyl groups at the a position to the carbonyl moiety, which are represented by the 2-aryltetralones, constitute key intermediates to biologically important compounds.[1] Although their preparation using a stoichiometric amount of chiral reagents has been reported, [1,2] their catalytic asymmetric synthesis has not been well developed. The palladium-or nickel-catalyzed asymmetric a-arylation [3] and a-alkenylation [4] of carbonyl compounds provides an efficient method for the synthesis of chiral ketones substituted with quaternary stereogenic centers, but their application to the asymmetric synthesis of products containing hydrogen at the chiral carbon should present a problem due to the difficulty in keeping the stereogenic character of the chiral carbon center bound to an acidic hydrogen under basic conditions at a high reaction temperature. Another important method of providing a-chiral ketones is the catalytic asymmetric protonation of enolates, [5][6][7] but the asymmetric synthesis at the stage of carbon-carbon bond formation is more desirable. Our approach is to apply the rhodium-catalyzed asymmetric 1,4-addition [8,9] to the asymmetric synthesis of a-aryl ketones. Herein we report that the asymmetric 1,4-addition of aryl-and alkenylboron reagents to quinone monoketals [10] is efficiently catalyzed by a chiral diene/rhodium complex [11][12][13][14] and one of the enantioenriched addition products (96-99 % ee) is readily converted into a 2-aryltetralone without loss of enantiomeric purity.

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Ruthenium‐Catalyzed CH Bond Activation of Michael Acceptors: An Unusual Reactivity Leading to Allylsilanes

et al. 2009

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Abstract:We report here an improved catalyst for the functionalization of Michael acceptors, involving C À C bond formation via C À H bond activation, using an in situ generated ruthenium active species. Moreover, on some particular substrates, the C À H functionalization resulted unexpectedly in the formation of allylsilanes rather than in the expected conjugated adducts, affording a new straightforward methodology to access useful stereodefined trisubstituted allylsilanes via C À H bond activation. Preliminary results have shown that they were reactive in the allylation of aldehydes, providing an access to alcohols bearing a quaternary carbon center.

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Enantioselektive Addition von Allyltrimethoxysilanen an Aldehyde mitp-Tol-BINAP⋅AgF als Katalysator

Cited by 31 publications

References 39 publications

Enantioselective Ag‐Catalyzed Allylation of Aldimines

Enantioselective Ag‐Catalyzed Allylation of Aldimines

Asymmetric 1,4‐Addition of Organoboron Reagents to Quinone Monoketals Catalyzed by a Chiral Diene/Rhodium Complex: A New Synthetic Route to Enantioenriched 2‐Aryltetralones

Ruthenium‐Catalyzed CH Bond Activation of Michael Acceptors: An Unusual Reactivity Leading to Allylsilanes

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