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Enantioselective and Enantiospecific Transition-Metal-Catalyzed Cross-Coupling Reactions of Organometallic Reagents To Construct C-C Bonds.

Cherney AH, Kadunce NT, Reisman SE - Chem. Rev. (2015)

View Article: PubMed Central - PubMed

Affiliation: The Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States.

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reagents in asymmetric alkyl cross-coupling reactions, with Hayashi, a single example of an asymmetric cross-coupling between sec-alkyl organic halides and organosilicon reagents has been reported stereoconvergent cross-coupling reactions between sec-alkyl electrophiles and either C(sp)- or C(sp)-hybridized organometallic reagents, Sestelo, Sarandeses, (Scheme 9a)... This result and π-allylmetal complex... Unselective reductive selectivity for the (Z)-alkene in most cases; MeMgBr resulted in decreased regioselectivity... increasing the C1–C1′ separation and disfavoring 1,1′ reductive elimination... use in asymmetric allylic alkylation reactions: any successful transformations the allenylmetal and its isomeric propargylmetal species prior to reductive elimination... the analogous asymmetric cross-coupling reactions of tert-alkyl partners represent a largely undeveloped area of great synthetic

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Cu-catalyzed asymmetric allylic arylation with arylboron reagents.
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fig75: Cu-catalyzed asymmetric allylic arylation with arylboron reagents.

Mentions: Until recently, there have been few reports of Cu-catalyzedstereoselectivecouplings of allylic electrophiles and C(sp2)-hybridizedorganoboron reagents. In 2011, Shintani, Hayashi, and co-workers discoveredthat CuCl, in conjunction with Mauduit-type NHC ligand L95(236,267) bearing a pendant hydroxyl group, catalyzesthe union of allylic phosphate 329 and boronate ester 363 (Figure 75).291,292 The use of NaOMe was important to favorformation of the branched product over the linear isomer. A wide scopeof arylboron reagents were well tolerated, and trisubstituted allylicphosphates could be employed to deliver all-carbon quaternary stereocenters.Moreover, a cyclohexenylboronate was coupled with only a small erosionof ee. The authors propose a mechanism in which transmetalation proceedsvia complex 365, in which the alcohol of L95 undergoes transesterification with the boronic acid. B to Cu transmetalation,followed by oxidative addition to phosphate 368, wouldgenerate σ-allylcopper complex 369. Reductive eliminationwould then provide product 370 and regenerate the Cucatalyst.


Enantioselective and Enantiospecific Transition-Metal-Catalyzed Cross-Coupling Reactions of Organometallic Reagents To Construct C-C Bonds.

Cherney AH, Kadunce NT, Reisman SE - Chem. Rev. (2015)

Cu-catalyzed asymmetric allylic arylation with arylboron reagents.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4566132&req=5

fig75: Cu-catalyzed asymmetric allylic arylation with arylboron reagents.
Mentions: Until recently, there have been few reports of Cu-catalyzedstereoselectivecouplings of allylic electrophiles and C(sp2)-hybridizedorganoboron reagents. In 2011, Shintani, Hayashi, and co-workers discoveredthat CuCl, in conjunction with Mauduit-type NHC ligand L95(236,267) bearing a pendant hydroxyl group, catalyzesthe union of allylic phosphate 329 and boronate ester 363 (Figure 75).291,292 The use of NaOMe was important to favorformation of the branched product over the linear isomer. A wide scopeof arylboron reagents were well tolerated, and trisubstituted allylicphosphates could be employed to deliver all-carbon quaternary stereocenters.Moreover, a cyclohexenylboronate was coupled with only a small erosionof ee. The authors propose a mechanism in which transmetalation proceedsvia complex 365, in which the alcohol of L95 undergoes transesterification with the boronic acid. B to Cu transmetalation,followed by oxidative addition to phosphate 368, wouldgenerate σ-allylcopper complex 369. Reductive eliminationwould then provide product 370 and regenerate the Cucatalyst.

View Article: PubMed Central - PubMed

Affiliation: The Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States.

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

reagents in asymmetric alkyl cross-coupling reactions, with Hayashi, a single example of an asymmetric cross-coupling between sec-alkyl organic halides and organosilicon reagents has been reported stereoconvergent cross-coupling reactions between sec-alkyl electrophiles and either C(sp)- or C(sp)-hybridized organometallic reagents, Sestelo, Sarandeses, (Scheme 9a)... This result and π-allylmetal complex... Unselective reductive selectivity for the (Z)-alkene in most cases; MeMgBr resulted in decreased regioselectivity... increasing the C1–C1′ separation and disfavoring 1,1′ reductive elimination... use in asymmetric allylic alkylation reactions: any successful transformations the allenylmetal and its isomeric propargylmetal species prior to reductive elimination... the analogous asymmetric cross-coupling reactions of tert-alkyl partners represent a largely undeveloped area of great synthetic

No MeSH data available.