Total synthesis of (+)-hyacinthacine A2 based on SmI2-induced nitrone umpolung.
[reaction: see text] A concise total synthesis of (+)-hyacinthacine A(2), a polyhydroxylated pyrrolizidine alkaloid, is described using our recently discovered inversion of the C-N bond polarity in nitrones. In the key step, the diastereoselective reductive coupling of a L-xylose-derived cyclic nitrone with ethyl acrylate allowed the assembly of the bicyclic core of the target molecule, by way of a tandem formation of the C-C and C-N bonds. The method opens a novel, short, and general route for the synthesis of other pyrrolizidine alkaloids.
Desvergnes
Stéphanie
S
LEDSS, UMR 5616 CNRS Institut de Chimie Moléculaire de Grenoble - FR 2607 Université Joseph Fourier, B.P. 53, 38041 Grenoble, France.
Py
Sandrine
S
Vallée
Yannick
Y
D001381:Azepines / Q000737:chemistry*; D007454:Iodides / Q000737:chemistry*; D008968:Molecular Conformation; D015394:Molecular Structure; D009589:Nitrogen Oxides / Q000737:chemistry*; D011758:Pyrroles / Q000737:chemistry*; D011763:Pyrrolizidine Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D012493:Samarium / Q000737:chemistry*
D001381:Azepines; D007454:Iodides; D009589:Nitrogen Oxides; D011758:Pyrroles; D011763:Pyrrolizidine Alkaloids; C015388:nitrones; C500285:pyrrolo(1,2-a)(1,4)diazepine; D012493:Samarium; C409809:samarium diiodide