Janssens J, De Roose M, Jacquemin A, Vanhosmael T, Delbrassinne A, Collard L, Robiette R. One-Carbon Homologation of Knoevenagel Adducts: Enantioselective Access to Benzhydryl Derivatives.
J Org Chem 2024;
89:7270-7274. [PMID:
38695495 DOI:
10.1021/acs.joc.4c00057]
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Abstract
A one-carbon homologation of Knoevenagel adducts enabling the insertion of a CHAr fragment is reported. The strategy involves a sulfur ylide mediated cyclopropanation followed by the rearrangement of cyclopropanes and enables the synthesis of a series of benzhydryl derivatives. Mechanistic studies reveal that the cyclopropane rearrangement involves a Lewis acid catalyzed ring-opening followed by the 1,2-migration of an aryl group. The possibility of controlling the absolute stereochemistry of the generated stereogenic allylic carbon center using a chiral sulfonium ylide is demonstrated.
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