Synthesis of the chiral auxiliary 1,3:4,6-di-O-benzylidene-2,5-dideoxy-2,5-imino-D-iditol
作者:Bernd Giese、Stephan N. Müller、Caroline Wyss、Hans Steiner
DOI:10.1016/0957-4166(96)00137-1
日期:1996.5
L-Mannitol 5, the precursor of the the C-2-symmetrical auxiliary 3B, was prepared in high yield by heterogeneous reduction of L-mannonic-gamma-lactone 4. The auxiliary 3B could be used for stereoselective photochemical synthesis of the L-proline derivative 2B. Copyright (C) 1996 Elsevier Science Ltd
Asymmetric Synthesis of 3-Hydroxyprolines by Photocyclization ofN-(2-Benzoylethyl)glycinamides
amides 1a-c were prepared from the C2-symmetric pyrrolidines 5a-c. Irradiation of these ketones 1a-c gave cis-3-hydroxyprolinamides 10-12 in moderate to good yields (Scheme 3). The de of the photocyclizations depended on the size of the substituents in positions C(2) and C(5) of the chiral pyrrolidine auxiliaries. In addition, the de varied with the reaction temperature, allowing the determination