Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2010 Mar 17;132(10):3612-20.
doi: 10.1021/ja910804u.

On the stereochemical course of palladium-catalyzed cross-coupling of allylic silanolate salts with aromatic bromides

Scott E Denmark  1 , Nathan S Werner
Affiliations

On the stereochemical course of palladium-catalyzed cross-coupling of allylic silanolate salts with aromatic bromides

Scott E Denmark et al. J Am Chem Soc. .

Abstract

The stereochemical course of palladium-catalyzed cross-coupling reactions of an enantioenriched, alpha-substituted, allylic silanolate salt with aromatic bromides has been investigated. The allylic silanolate salt was prepared in high geometrical (Z/E, 94:6) and high enantiomeric (94:6 er) purity by a copper-catalyzed S(N)2' reaction of a resolved allylic carbamate. Eight different aromatic bromides underwent cross-coupling with excellent constitutional site-selectivity and excellent stereospecificity. Stereochemical correlation established that the transmetalation event proceeds through a syn S(E)' mechanism which is interpreted in terms of an intramolecular delivery of the arylpalladium electrophile through a key intermediate that contains a discrete Si-O-Pd linkage.

PubMed Disclaimer

Figures

Figure 1
Figure 1
General classification of asymmetric transition metal-catalyzed cross-coupling reactions.
Figure 2
Figure 2
Stereochemical control elements in SE’ reactions (CIP: E > CH=CH > R1).
Figure 3
Figure 3
Synthetic Strategy to Determine the Stereochemical Course of Transmetalation.
Figure 4
Figure 4
Possible pathways for the transmetalation of allylic silanolates. (R = i-Bu, RE = reductive elimination).
Figure 5
Figure 5
Refined catalytic cycle.
Scheme 1<sup>a</sup>
Scheme 1a
Scheme 2
Scheme 2
Scheme 3
Scheme 3
Scheme 4
Scheme 4
Scheme 5
Scheme 5
Scheme 6
Scheme 6
Scheme 7<sup>a</sup>
Scheme 7a
See this image and copyright information in PMC

References

    1. de Meijere A, Diederich F, editors. Metal-Catalyzed Cross-Coupling Reactions. Second Ed. Weinheim: Wiley-VCH; 2004.
    2. Negishi E-I, editor. Handbook of Organopalladium Chemistry for Organic Synthesis. New York: Wiley–Interscience; 2002.
    1. Ojima I, editor. Catalytic Asymmetric Synthesis. Second Ed. New York: Wiley–VCH; 2000.
    2. Tietze LF, Ila H, Bell HP. Chem. Rev. 2004;104:3453–3516. - PubMed
    3. Hayashi TJ. Organomet. Chem. 2002;653:41–45.
    4. Hayashi T. Chapt. 25. In: Jacobsen EN, Pfaltz A, Yamamoto H, editors. Comprehensive Asymmetric Catalysis. Vol. II. Heidelberg: Springer Verlag; 1999.
    5. Blystone SL. Chem. Rev. 1989;89:1663–1679.

    1. The trivial case of cross-coupling of chiral subunits where the newly formed carbon–carbon bond is not a stereogenic unit are excluded.

    1. By far the largest category of transition metal-catalyzed, carbon-carbon and carbon-heteroatom bond forming reactions involves the asymmetric capture of π-allyl-metals derived from palladium, molybdenum, rhodium and iridium with a wide range of nucleophiles. These powerful reactions have been thoroughly reviewed and therefore will not be categorized here, see: Lu Z, Ma S. Angew. Chem., Int. Ed. 2008;47:258–297. Trost BM, Crawley ML. Chem. Rev. 2003:2921–2943. Pfaltz A, Lautens M. Chapt. 24. In: Jacobsen EN, Pfaltz A, Yamamoto H, editors. Comprehensive Asymmetric Catalysis. Vol. II. Heidelberg: Springer Verlag; 1999.

    1. For a definition of internal and external selection see: Denmark SE, Almstead NG. Allylation of Carbonyls: Methodology and Stereochemistry. In: Otera J, editor. Modern Carbonyl Chemistry. Weinheim: Wiley–VCH; 2000. pp. 299–402.

Publication types