Homochiral 2,2′-bis(oxazolyl)-1,1′-binaphthyls as ligands for copper(I)-catalyzed asymmetric cyclopropanation

✍ Scribed by Yasuhiro Uozumi; Hirokazu Kyota; Eiji Kishi; Kenji Kitayama; Tamio Hayashi

• Book ID: 103977519
• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 252 KB
• Volume: 7
• Category: Article
• ISSN: 0957-4166
• DOI: 10.1016/0957-4166(96)00193-0

✦ Synopsis

Homochiral 2,2'-bis [4-(alkyl)oxazol-2-yl]-l,l'-binaphthyls, which possess both binaphthyl axial chirality and carbon centred chirality, were prepared from 1,1'-binaphthyl-2,2'-dicarboxylic acid and 2-alkyl-2-aminoethanols in high yields. Asymmetric cyclopropanation of styrene with diazoacetates in the presence of 2 mol % of copper(l) triflate and (S) -2,2 'bis[(S)-4-(t-butyl)oxazol-2-yl]-1, l'-binaphthyl gave optically active 2-(phenyl)eyclopropanecarboxylates of up to 97% ee.