Total synthesis and confirmation of the absolute stereochemistry of semiviriditoxin, a naphthopyranone metabolite from the fungus Paecilomyces variotii
作者:Nichole P.H. Tan、Christopher D. Donner
DOI:10.1016/j.tet.2009.03.016
日期:2009.5
The first total synthesis of (S)-semiviriditoxin 2 is described. The approach utilizes a tandem Michael–Dieckmann reaction between ortho-toluate 5 and dihydropyran-2-one 6 to construct the naphthopyranone core, the dihydropyran-2-one 6 being prepared from (R)-1,2-epoxy-4-butanol. Spectroscopic comparison of synthetic (S)-semiviriditoxin 2 with (R)-semivioxanthin 3, prepared in four steps from (R)-propylene
Naphthopyranone synthesis via the tandem Michael–Dieckmann reaction of ortho-toluates with 5,6-dihydropyran-2-ones
作者:Nichole P.H. Tan、Christopher D. Donner
DOI:10.1016/j.tetlet.2008.04.112
日期:2008.6
The tandem Michael-Dieckmann reaction between a series of ortho-toluates and the alpha,beta-unsaturated lactone 25 is described. The tandem reaction delivers substituted naphthopyranones in moderate (20-49%) yields, whilst limitations in the tolerance of this reaction for different substituents on the ortho-toluate are identified. Crown Copyright (C) 2008 Published by Elsevier Ltd. All rights reserved.