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A Highly Selective Ferrocene-Based Planar Chiral PIP (Fc-PIP) Acyl Transfer Catalyst for the Kinetic Resolution of Alcohols
Ist Teil von
Journal of the American Chemical Society, 2010-12, Vol.132 (47), p.17041-17044
Ort / Verlag
United States: American Chemical Society
Erscheinungsjahr
2010
Quelle
MEDLINE
Beschreibungen/Notizen
Novel planar chiral ferrocene nucleophilic catalysts (Fc-PIP) containing both central and planar chiral elements were designed and synthesized for catalytic enantioselective acyl transfer of secondary alcohols. A remarkably efficient catalyst with high selectivity factors (up to S = 1892) was identified. Comparing the combination of central and planar chirality revealed a strong requirement for the “matched” chiral elements, indicating that the stereogenic center of the imidazole rings should present itself on the same face as the ferrocenyl fragment; otherwise, the catalyst is completely inactive. An exclusively stacked transition state that accounts for the high selectivity of the kinetic resolution of secondary alcohols is proposed. Notably, this newly designed catalyst family is suitable for the catalytic kinetic resolution of bulky arylalkyl carbinols, producing esters with extremely high ee (>99%).