2568-36-7Relevant academic research and scientific papers
Divergent Synthesis of Bioactive Dithiodiketopiperazine Natural Products Based on a Double C(sp3)?H Activation Strategy
Thesmar, Pierre,Coomar, Seemon,Prescimone, Alessandro,H?ussinger, Daniel,Gillingham, Dennis,Baudoin, Olivier
supporting information, p. 15298 - 15312 (2020/10/21)
This article provides a detailed report of our efforts to synthesize the dithiodiketopiperazine (DTP) natural products (?)-epicoccin G and (?)-rostratin A using a double C(sp3)?H activation strategy. The strategy's viability was first established on a model system lacking the C8/C8’ alcohols. Then, an efficient stereoselective route including an organocatalytic epoxidation was secured to access a key bis-triflate substrate. This bis-triflate served as the functional handles for the key transformation of the synthesis: a double C(sp3)?H activation. The successful double activation opened access to a common intermediate for both natural products in high overall yield and on a multigram scale. After several unsuccessful attempts, this intermediate was efficiently converted to (?)-epicoccin G and to the more challenging (?)-rostratin A via suitable oxidation/reduction and protecting group sequences, and via a final sulfuration that occurred in good yield and high diastereoselectivity. These efforts culminated in the synthesis of (?)-epicoccin G and (?)-rostratin A in high overall yields (19.6 % over 14 steps and 12.7 % over 17 steps, respectively), with the latter being obtained on a 500 mg scale. Toxicity assessments of these natural products and several analogues (including the newly synthesized epicoccin K) in the leukemia cell line K562 confirmed the importance of the disulfide bridge for activity and identified dianhydrorostratin A as a 20x more potent analogue.
SilverCatalyzed Cascade Carboxylation and Cyclization of Trimethyl(2-methylenebut-3-yn-1-yl)silane Derivatives
Sekine, Kohei,Sadamitsu, Yuta,Yamada, Tohru
supporting information, p. 5706 - 5709 (2015/12/01)
C-C bond-forming carboxylation and cyclization of trimethyl(2-methylenebut-3-yn-1-yl)silane derivatives and carbon dioxide was developed. Silver catalysts and CsF promoted the reaction to afford the corresponding 2-furanone and 2-pyrone derivatives in goo
Catalytic formal homo-Nazarov cyclization
De Simone, Filippo,Andres, Julien,Torosantucci, Riccardo,Waser, Jerome
supporting information; experimental part, p. 1023 - 1026 (2009/07/18)
The first catalytic method for the cyclization of vinyl-cyclopropyl ketones (formal homo-Nazarov reaction) is reported. Starting from activated cyclopropanes, heterocyclic, and carbocyclic compounds were obtained under mild conditions using Bronsted acid catalysts. Preliminary investigation of the reaction mechanism indicated a stepwise process.
Thermal intramolecular Diels-Alder reaction of furan; synthesis of nitrogen tetracycles, isobenzofuran and isobenzothiophene
Karaarslan, Muhsin,Gokturk, Ersen,Demircan, Aydin
, p. 117 - 120 (2008/02/02)
Thermal intramolecular Diels-Alder (IMDA) reaction of furan cored compounds has been further investigated; a series of key precursors to the IMDA reaction of furan diene (9a-c) have been prepared via facile alkylation and protection. While the cycloadditi
Concise assembly of the polycyclic frameworks associated with the hapalindole and fischerindole alkaloids
Banwell, Martin G.,Ma, Xinghua,Taylor, Rebecca M.,Willis, Anthony C.
, p. 4959 - 4961 (2007/10/03)
Reaction of N-methylindole (4) with 6,6-dibromobicyclo[3.1.0]hexane (5) in the presence of silver tetrafluoroborate affords conjugate 7 in 67% yield. This product can be readily elaborated to compounds 12b and 13b which embody the polycyclic frameworks as
Convergent Routes to the Dioxolophenanthridin-6(5H)-one and 2,3,4,4a-Tetrahydrodioxolophenanthridin-6(5H)-one Nuclei. Application to Syntheses of the Amaryllidaceae Alkaloids Crinasiadine, N-Methylcrinasiadine and Trisphaeridine
Banwell, Martin G.,Cowden, Cameron J.
, p. 2235 - 2254 (2007/10/02)
Convergent routes to the title nuclei, (1) and (6), have been developed.Thus, Suzuki coupling of boronic acid (8) with aryl bromide (9) gave the biarylylcarbamate (7) which, on treatment with phosphorus oxychloride (POCl3), underwent Bischler-Napieralski
A Novel Synthesis of Transient 1,2-Cyclohexa-diene and 1,2-Cycloheptadiene via β-Halosilanes
Sutbeyaz, Yasar,Ceylan, Mustafa,Secen, Hasan
, p. 2189 - 2196 (2007/10/02)
A new method was developed to synthesize transient 1,2-cyclohexadiene and 1,2-cycloheptadiene.Fluoride ion-promoted elimination of 4 and 11 gave strained cyclic allenes 5 and 12, where 14 failed to react.
RELATIVE REACTIVITY OF CYCLOOLEFINS TOWARD DICHLOROCARBENES
Kostikov, R. R.,Molchanov, A. P.,Muehlstaedt, M.,Kuhl, P.
, p. 1062 - 1065 (2007/10/02)
The relative rate constants for the addition of dichloro- and dibromocarbenes to cis- and trans-cycloalkenes, containing up to 12 carbon atoms in the ring, were determined.It was shown that the reaction is kinetically controlled and that the conformation of the ring exerts an important effect on the rate.
