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Isoxazole‐Embedded Allylic Zinc Reagent for the Diastereoselective Preparation of Highly Functionalized Aldol‐Type Derivatives Bearing a Stereocontrolled Quaternary Center
Author(s) -
Klier Lydia,
Diène Coura R.,
Schickinger Manuel,
Metzger Albrecht,
Wagner Andreas J.,
Karaghiosoff Konstantin,
Marek Ilan,
Knochel Paul
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201402733
Subject(s) - allylic rearrangement , aldol reaction , chemistry , reagent , electrophile , aryl , medicinal chemistry , isoxazole , zinc , reactivity (psychology) , organic chemistry , stereochemistry , catalysis , alkyl , medicine , alternative medicine , pathology
Highly functionalized aldol‐type products bearing a β‐quaternary center and a stereoselectively controlled γ‐hydroxy function are readily prepared by the diastereoselective addition of an allylic zinc reagent embedded in an isoxazole ring to various aromatic and heteroaromatic aldehydes, in the presence of Lewis acids, such as MgCl 2 or LaCl 3 ⋅2 LiCl. After reductive cleavage of the NO bond by using Fe, NH 4 Cl, aldol‐type products bearing a stereocontrolled β‐quaternary center and a γ‐hydroxy group were observed. The benzylic reactivity of the isoxazolylmethylzinc reagent towards other electrophiles, such as acid chlorides, aryl and allylic halides, as well as aldehydes in the presence of BF 3 ⋅OEt 2 are also described.