作者:Steven M Allin、William R.S Barton、W.Russell Bowman、Tom McInally
DOI:10.1016/s0040-4039(01)01639-2
日期:2001.10
Synthetically useful [1,2-a]-fused pyrroles, e.g. 2,3-dihydro-1H-pyrrolizidines substituted in the 1- and 7-positions, have been generated by acyl radical cyclisation onto pyrroles using N-(omega -acyl)-radicals generated front acyl-selenide precursors. The protocol does not require high pressures of CO. Mechanistic studies indicate the key role of azo radical initiators as oxidants of the intermediate pi -radicals. (C) 2001 Elsevier Science Ltd. All rights reserved.
Total synthesis of two novel 5,6,7,8-tetrahydroindolizine alkaloids, polygonatines A and B
作者:Andrew Dinsmore、Karen Mandy、Joseph P. Michael
DOI:10.1039/b517573a
日期:——
polygonatines A and B, two simple but structurally novel alkaloids, have been substantiated by synthesis. Cyclisation of 4-(1H-pyrrol-1-yl)butanoic acid or its ethyl ester produced 6,7-dihydroindolizin-8(5H)-one , formylation of which at C-3 followed by reduction afforded polygonatine A . Acetylation of this alkaloid followed by displacement of the acetate with ethanol yielded polygonatine B , possibly via