Gold-Catalyzed Intramolecular Oxidative Cross-Coupling of Nonactivated Arenes
作者:Matthew N. Hopkinson、Arnaud Tessier、Andrew Salisbury、Guy T. Giuffredi、Lorraine E. Combettes、Antony D. Gee、Véronique Gouverneur
DOI:10.1002/chem.201000322
日期:2010.4.26
An (Au)some coupling! Gold‐catalyzed cascade CO cyclizations of benzyl‐substituted allenoate esters followed by intramolecular oxidative CC cross‐coupling involving aryl CH functionalization were performed with Selectfluor as the oxidant (see scheme). This operationally simple and mild procedure benefits from complete axis‐to‐center chirality transfer and allows for the preparation of surprisingly
AuCl3 efficiently catalyzes cyclization of tert-butyl allenoates into γ-butenolides. Advantage of directly using allenic ester precursor instead of corresponding acid is demonstrated in the synthesis of a variety of 2,4-disubstituted butenolides. A low catalyst loading and mild reaction condition makes this process an attractive alternative over conventional methods using strong Lewis acids.