Construction of the A-ring of cylindrospermopsin via an intramolecular oxazinone-N-oxide dipolar cycloaddition
作者:Ryan E Looper、Robert M Williams
DOI:10.1016/s0040-4039(00)01921-3
日期:2001.1
The efficient synthesis of an A-ring synthon for the marine hepatatoxin cylindrospermopsin has been achieved. The key step features an intramolecular oxazinone N-oxide/alkene dipolarcycloaddition resulting in the establishment of the three contiguous stereogenic centers in the A-ring from one pre-existing stereogenic center in a single step.
A Concise Asymmetric Synthesis of the Marine Hepatotoxin 7-Epicylindrospermopsin
作者:Ryan E. Looper、Robert M. Williams
DOI:10.1002/anie.200454208
日期:2004.5.24
Syntheses of the cylindrospermopsin alkaloids
作者:Ryan E. Looper、Maria T.C. Runnegar、Robert M. Williams
DOI:10.1016/j.tet.2006.02.044
日期:2006.5
An intramolecular 1,3-dipolar cycloaddition has efficiently constructed the A-ring portions of the cylindrospermopsin alkaloids. A nitro-aldol addition of an elaborated nitroalkane to a pyrimidine aldehyde followed by an intramolecular reductive guanidinylation has enabled the syntheses of all three alkaloids in this family in 18-19 steps. We report the first asymmetric synthesis of cylindrospermopsin, unambiguously assigning its absolute configuration. (c) 2006 Elsevier Ltd. All rights reserved.