Polyhydroxylated pyrrolidines: synthesis from d-fructose of new tri-orthogonally protected 2,5-dideoxy-2,5-iminohexitols
作者:Isidoro Izquierdo、María T. Plaza、Victor Yáñez
DOI:10.1016/j.tet.2006.11.070
日期:2007.2
The readily available 3-O-benzyl-1,2-O-isopropylidene-beta-D-fructopyranosc (2) was transformed into its 5-O-(3) and 4-O-benzoyl (4) derivative. Compound 4 was straightforwardly transformed into 5-azido-4-O-benzoyl-3-O-benzyl-5-deoxy-1,2-O-isopropylidene-beta D-fructopyranose (7) via the corresponding 5-deoxy-5-iodo-alpha-L-sorbopyranose derivative 6. Cleavage of the acetonide in 7 to give 8, followed by regioselective 1-O-silylation to 9 and subsequent catalytic hydrogenation gave a mixture of (2S,3R,4R,5R)-(10) and (2R,3R,4R,5R)-4-benzoyloxy-3-benzyloxy-2'-O-tert-butyldiphenylsilyl-2,5-bis(hydroxymethyl)pyrrolidine (12) that was resolved after chemoselective N-protection as their Cbz derivatives 11 and la, respectively. Stereochemistry of 11 and la could be determined after total deprotection of 11 to the well known DGDP (13). Compound 2 was similarly transformed into the tri-orthogonally protected DGDP derivative 18. (c) 2006 Elsevier Ltd. All rights reserved.