Universität zu Köln

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

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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:	Creators Email ORCID ORCID Put Code Bruellingen, Eric UNSPECIFIED UNSPECIFIED UNSPECIFIED Neudoerfl, Joerg-Martin UNSPECIFIED UNSPECIFIED UNSPECIFIED Goldfuss, Bernd UNSPECIFIED orcid.org/0000-0002-1814-8818 UNSPECIFIED
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:	Keywords Language DIALKYLZINC ADDITIONS; N-BUTYLLITHIUM; (PHOSPHANYLOXAZOLINE)PALLADIUM COMPLEXES; DENSITY FUNCTIONALS; NMR INVESTIGATIONS; FLUORINE; LITHIUM; THERMOCHEMISTRY; HYBRIDIZATION; SUBSTITUTION Multiple languages Chemistry, Multidisciplinary Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/13062