Total synthesis of natural (+)-hyacinthacine A6 and non-natural (+)-7a-epi-hyacinthacine A1 and (+)-5,7a-diepi-hyacinthacine A6
作者:Isidoro Izquierdo、María T. Plaza、Juan A. Tamayo、Francisco Franco、Fernando Sánchez-Cantalejo
DOI:10.1016/j.tet.2010.03.049
日期:2010.5
Naturally occurring (1S,2R,3R,5R,7aR)-1,2-dihydroxy-3-hydroxymethyl-5-methylpyrrolizidine [(+)-hyacinthacine A(6), 2] together with unnatural (1S,2R,3R,7aS)-1,2-dihydroxy-3-hydroxy-methylpyrrolizidine [(+)-7a-epi-hyacinthacine A(1), 3] and (1S,2R,3R,5S,7aS)-1,2-dihydroxy-3-hydroxy-methyl-5-methylpyrrolizidine [(+)-5,7a-diepi-hyacinthacine A(6), 4] have been synthesized from a DALDP derivative [5, (2R,35,4R,5R)-3,4-dibenzyloxy-2'-O-tert-butyldiphenylsilyl-2,5-bis(hydroxymethyl)-pyrrolidine], as the homochiral starting material. The synthetic process employed took advantages of Wittig methodology followed by internal lactamization, in the case of (+)-7a-epi-hyacinthacine A(1) (3), and reductive amination for (+)-hyacinthacine A(6) (2) and (+)-5,7a-diepi-hyacinthacine A(6) (4). (C) 2010 Elsevier Ltd. All rights reserved.