Bruellingen, Eric, Neudoerfl, Joerg-Martin and Goldfuss, Bernd ORCID: 0000-0002-1814-8818
(2019).
Ligand's electronegativity controls the sense of enantioselectivity in BIFOP-X palladium-catalyzed allylic alkylations.
New J. Chem., 43 (39).
S. 15743 - 15754.
CAMBRIDGE:
ROYAL SOC CHEMISTRY.
ISSN 1369-9261
Abstract
Palladium-catalyzed allylic alkylations of sodium dimethyl malonate with 1,3-diphenylallyl acetate, employing BIFOP-H (biphenylbisfencholphosphite) and analogue (i.e. BIFOP-X, X = D, Cl, CN, N-3) ligands, all yield (S)-enantiomeric products, while alkylations to cyclohexenyl acetate yield the (R)-enantiomeric C-C coupling product (up to 91% yield, 70% ee). The fluoro derivative BIFOP-F however, switches the sense of enantioselectivity, yielding the (R)-enantiomer for 1,3-diphenylallyl acetate and the (S)-enantiomer for the cyclohexenyl acetate (up to 92% yield, 67% ee). Computational analyses of transition structures (M06-2X-D3/def2-TZVP//B3LYP-D3(BJ)/def2-SVP) for these Pd-catalyzed allylic alkylations reproduce the experimental preference of BIFOP-H (and analogue BIFOP-X ligands) for (R)- or (S)-enantiomeric products of 1,3-diphenylallyl or cyclohexenyl acetate, respectively. The F-switch of the sense of enantioselectivity from BIFOP-H to BIFOP-F is also apparent computationally and is found (NBO-analyses) to originate from lp(Pd) -> sigma*(P-O) or lp(Pd) -> sigma*(P-F) hyperconjugations. The higher electronegativity of F vs. H in BIFOP-X hence controls the sense of enantioselectivity of this Pd-catalyzed allylic alkylation.
Item Type: | Journal Article | ||||||||||||||||
Creators: |
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URN: | urn:nbn:de:hbz:38-130624 | ||||||||||||||||
DOI: | 10.1039/c9nj02798j | ||||||||||||||||
Journal or Publication Title: | New J. Chem. | ||||||||||||||||
Volume: | 43 | ||||||||||||||||
Number: | 39 | ||||||||||||||||
Page Range: | S. 15743 - 15754 | ||||||||||||||||
Date: | 2019 | ||||||||||||||||
Publisher: | ROYAL SOC CHEMISTRY | ||||||||||||||||
Place of Publication: | CAMBRIDGE | ||||||||||||||||
ISSN: | 1369-9261 | ||||||||||||||||
Language: | English | ||||||||||||||||
Faculty: | Faculty of Mathematics and Natural Sciences | ||||||||||||||||
Divisions: | Faculty of Mathematics and Natural Sciences > Department of Chemistry > Institute of Organic Chemistry | ||||||||||||||||
Subjects: | no entry | ||||||||||||||||
Uncontrolled Keywords: |
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Refereed: | Yes | ||||||||||||||||
URI: | http://kups.ub.uni-koeln.de/id/eprint/13062 |
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