Stereoselective Synthesis of α‐Fluorinated Amino Acid Derivatives

• DOI: 10.1002/adsc.201000506
• Publication Date: 2010-10-26T06:51:30Z
• Authors: Atsushi Tarui; Kazuyuki Sato; Masaaki Omote; Itsumaro Kumadaki; Akira Ando
• Keywords: Diethylzinc; Reformatsky reaction; Diethyl ether

Abstract This account concentrates on our new methodologies for the synthesis of fluorine analogues amino acids and their derivatives using Reformatsky‐type reactions ethyl bromodifluoroacetate dibromofluoroacetate with imines promoted by Wilkinson catalyst. First, we present rhodium‐catalyzed reaction diethylzinc chemoselective α,α‐difluoro‐β‐lactams non‐cyclized products, 3‐alkylamino‐2,2‐difluorocarboxylates. was expanded to asymmetric difluoro‐β‐lactams two types chiral auxiliaries. To develop another methodology monofluoro derivatives, investigated diethylzinc, found that this proceeded without a rhodium catalyst in diethyl ether give syn ‐α‐bromo‐α‐fluoro‐β‐lactams stereoselectively. Interestingly, changing solvent acetonitrile, aza‐Darzens ‐2‐fluoroaziridine‐2‐carboxylates, were obtained chemo‐