Highly sterically hindered binaphthalene-based monophosphane ligands: synthesis and application in stereoselective Suzuki–Miyaura reactions
作者:Michaela Mešková、Martin Putala
DOI:10.1016/j.tetasy.2013.06.007
日期:2013.8
A series of new sterically hindered (R)-(2′-aryl-1,1′-binaphthalene-2-yl)phosphanes with ortho-substituted phenyls as aryl groups were prepared via Negishi monoarylation of enantiopure 2,2′-dibromo-1,1′-binaphthalene followed by lithiation and quenching with diphenylphosphanyl or dicyclohexylphosphanyl chloride. These ligands were applied to the stereoselective Suzuki–Miyaura coupling for the preparation
The diastereoselective addition of organozinc species to 1,2-anhydro sugars in toluene/n-dibutyl ether solvent is reported. Compared to the existing methods, the reaction proceeds at 0 degrees C, and only a slight excess of nucleophile is required to achieve good yields. Scope was assessed with different Omicron-protected glycals along with various nucleophiles (aryl, alkynyl). This methodology was applied to the synthesis of the alpha-anomer of canagliflozin.