Herein, we describe a concise total synthesis of dalesconol A through a "polycyclization/oxidation" approach. In the polycyclization stage, a Pd(0)/NBE-catalyzed 3-fold domino reaction and a subsequent intramolecular Michael addition have been utilized for the one-step assembly of the heptacyclic molecular skeleton. In the late stage of oxidation state adjustments, a stepwise sequence including site-selective benzylic oxidation, Pd(II)-catalyzed oxime ether directed trihydroxylation, and desaturation has been adopted to introduce the oxygen functionalities and furnish the synthesis of dalesconol A. With the advantage of the late-stage amidation of three C-H bonds in a single step, the amino analogue of dalesconol A has also been obtained with high efficiency.
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http://dx.doi.org/10.1021/jacs.1c12118 | DOI Listing |
J Am Chem Soc
December 2021
Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, College of Chemistry & Materials Science, Northwest University, Xi'an 710127, People's Republic of China.
Herein, we describe a concise total synthesis of dalesconol A through a "polycyclization/oxidation" approach. In the polycyclization stage, a Pd(0)/NBE-catalyzed 3-fold domino reaction and a subsequent intramolecular Michael addition have been utilized for the one-step assembly of the heptacyclic molecular skeleton. In the late stage of oxidation state adjustments, a stepwise sequence including site-selective benzylic oxidation, Pd(II)-catalyzed oxime ether directed trihydroxylation, and desaturation has been adopted to introduce the oxygen functionalities and furnish the synthesis of dalesconol A.
View Article and Find Full Text PDFNat Prod Rep
October 2021
Shenzhen Grubbs Institute and Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen 518055, China.
Covering: 2010 to 2020Benzocycloheptane is a fundamental and unique structural motif found in pharmaceuticals and natural products. The total syntheses of natural products bearing the benzocycloheptane subunit are challenging and there are only a few efficient approaches to access benzocycloheptane. Thus, new methods and innovative strategies for preparing such natural products need to be developed.
View Article and Find Full Text PDFJ Biosci Bioeng
February 2018
State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, PR China.
Dalesconols (dalesconols A and B) were isolated from Daldinia eschscholzii and have remarkable immunosuppressive activity. In this study, the response of fungal growth, intra- and extracellular Ca, and dalesconols production after CaCl addition were reported for the first time. After supplementation with 5 mM Ca at 24 h, dalesconols production reached 84.
View Article and Find Full Text PDFOrg Lett
April 2017
State Key Laboratory of Pharmaceutical Biotechnology, Institute of Functional Biomolecules, Nanjing University, Nanjing 210046, China.
Microbial constructions of secondary metabolites are generally biosynthetic gene cluster (BGC)-based, and the forging of different BGC-sourced intermediates tends to be overlooked. Here, we show that the dalesconol bioassembly lines in Daldinia eschscholzii can sequester guest intermediates (i.e.
View Article and Find Full Text PDFJ Am Chem Soc
March 2017
State Key Laboratory of Bio-Organic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences , 345 Ling Ling Road, Shanghai 200032, China.
We herein report the first enantioselective syntheses of immunosuppressants (+)-dalesconol A and B in a highly efficient and concise manner, which features an efficient palladium-catalyzed enantioselective dearomative cyclization-kinetic resolution cascade to install the chiral all-carbon quaternary center, an effective sterically hindered Stille coupling, a powerful 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) oxidation to furnish all requisite unsaturation, and a tandem hydrolysis-ring closure sequence.
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