A new synthetic access to bicyclic polyhydroxylated alkaloid analogues from pyranosides
作者:Ning Wang、Li-He Zhang、Xin-Shan Ye
DOI:10.1039/b923180c
日期:——
A facile, versatile and stereoselective synthesis of bicyclic polyhydroxylated alkaloids as castanospermineanalogues is described. The synthetic route started from methyl pyranosides. The key steps involved a high-yielding expeditious one-pot tandem reaction from alkenes to N-substituted δ-lactams. The δ-lactams were stereoselectively vinylated to give the dienes, which were followed by the ring-closing
Divergent total synthesis of 1,6,8a-tri-epi-castanospermine and 1-deoxy-6,8a-di-epi-castanospermine from substituted azetidin-2-one (β-lactam), involving a cascade sequence of reactions as a key step
作者:Dipak Kumar Tiwari、Kishor Chandra Bharadwaj、Vedavati G. Puranik、Dharmendra Kumar Tiwari
DOI:10.1039/c4ob00948g
日期:——
divergent, short, and novel total synthesis of 1,6,8a-tri-epi-castanospermine (7) and 1-deoxy-6,8a-di-epi-castanospermine (8) has been developed via a common precursor, 15, obtained fromD-mannitolderived β-lactam. The key step involves a one pot cascade sequence of trimethyl sulfoxonium ylide based cyclization of epoxy sulfonamide 14via epoxide ring opening, one carbon homologation followed by intramolecular
Synthesis of 1-deoxy-6-epicastanospermine and 1-deoxy-6,8a-diepicastanospermine
作者:Kai H. Aamlid、Leslie Hough、Anthony C. Richardson
DOI:10.1016/0008-6215(90)84075-6
日期:1990.7
then gave a mixture of pyrrolidines. After sulphonylation at the terminal 8-position, the pyrrolidines were then cyclised further between the nitrogen and C-8 to give 1-deoxy-6-epicastanospermine and 1-deoxy-6,8a-diepicastanospermine.
Asymmetric syntheses of both 1-deoxy-6,8a-di-epi-castanospermine and 1-deoxy-6-epi-castanospermine, polyhydroxylated indolizidine alkaloids that act as selective glycosidase inhibitors, have been accomplished in seven steps. The key feature of our unique syntheses includes the stereoselective introduction of the C-3 and C-4 hydroxyl groups utilizing the aza-Claisen rearrangement-induced ring expansion of 1-acyl-2-alkoxyvinyl pyrrolidine and a substrate-controlled stereoselective transannulation of the resulting azoninone intermediate.
AAMLID, KAI H.;HOUGH, LESLIE;RICHARDSON, ANTHONY C., CARBOHYDR. RES., 202,(1990) C. 117-129
作者:AAMLID, KAI H.、HOUGH, LESLIE、RICHARDSON, ANTHONY C.