Progress toward the welwitindolinone alkaloid N-methylwelwitindolinone B isothiocyanate is reported. A key reaction to synthesize the [4.3.1] bicycle embedded in the core of the molecule is a furan type 2 intramolecular Diels-Alder reaction with a tetrasubstituted dienophile, which sets the two vicinal quaternary centers present in the natural product. The sterically encumbered cycloaddition precursor was synthesized using a Horner-Wadsworth-Emmons reaction followed by a Suzuki cross-coupling reaction. Finally, introduction of the secondary alkyl chloride was achieved by a regio- and diastereoselective opening of a [2.2.1] oxobicycloheptane functionality.
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http://dx.doi.org/10.1021/ol5020043 | DOI Listing |
Yakugaku Zasshi
February 2018
Graduate School of Biomedical Sciences, Nagasaki University.
This review article describes the total syntheses of englerin A, ophiodilactones A and B, marinomycin A, N-methylwelwitindolinone C isothiocyanate, tirandamycins A-D, and tirandalydigin, which possess intriguing biological activities and challenging structures with characteristic ring systems. The focus is on the synthetic methodologies that lead to the highly stereocontrolled assembly of these natural products.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
August 2017
Department of Chemistry, University of Chicago, 5735 South Ellis Avenue, Chicago, IL, 60637, USA.
The asymmetric synthesis of (-)-N-methylwelwitindolinone B isothiocyanate is reported. Critical challenges overcome through these studies include the stereoselective installation of the sterically congested C13 alkyl chloride and control of the wayward reactivity of the indole unit to standard oxidants. A Pt-catalyzed hydrosilylation helped stymie unwanted rearrangements facilitated by vinyl group participation during the chloride installation step, and a new Fe -catalyzed oxidation accomplished the problematic conversion of indole into 2-indolinone.
View Article and Find Full Text PDFOrg Lett
August 2015
Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8521, Japan.
The highly stereocontrolled total synthesis of (-)-N-methylwelwitindolinone C isothiocyanate is described, which features the expeditious construction of a bicyclo[4.3.1]decane ring system by a palladium-catalyzed tandem enolate allylation/arylation reaction.
View Article and Find Full Text PDFJ Am Chem Soc
October 2014
Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States.
The first total synthesis of N-methylwelwitindolinone B isothiocyanate is reported. The route features several key steps, including a regio- and diastereoselective chlorinative oxabicycle ring-opening reaction to introduce the challenging alkyl chloride motif.
View Article and Find Full Text PDFOrg Lett
September 2014
Department of Chemistry, University of California, Irvine , 1102 Natural Sciences 2, Irvine, California 92697-2025, United States.
Progress toward the welwitindolinone alkaloid N-methylwelwitindolinone B isothiocyanate is reported. A key reaction to synthesize the [4.3.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!