Self‐Assembly of Disorazole C<sub>1</sub> through a One‐Pot Alkyne Metathesis Homodimerization Strategy

Ralston, Kevin J.; Ramstadius, H. Clinton; Brewster, Richard C.; Niblock, Helen S.; Hulme, Alison N.

doi:10.1002/ange.201501922

Cited by 33 publications

(3 citation statements)

References 56 publications

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“…The syntheses could partially be based on literature procedures and were therefore straightforward. For linker 1 with the ( S )-configuration, , the synthesis is completely according to the known literature procedure and we followed those procedures. − Linker 1 was subsequently protected at the primary hydroxy function with the DMT group in 68% yield using the standard procedure. Finally, 3 was converted to H-phosphonate 4 in 69% yield.…”

Section: Resultsmentioning

confidence: 99%

Hybridization-Sensitive Fluorescent Probes for DNA and RNA by a Modular “Click” Approach

et al. 2022

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Fluorescent DNA probes were prepared in a modular approach using the “click” post-synthetic modification strategy. The new glycol-based module and DNA building block place just two carbons between the phosphodiester bridges and anchor the dye by an additional alkyne group. This creates a stereocenter in the middle of this artificial nucleoside substitute. Both enantiomers and a variety of photostable cyanine–styryl dyes as well as thiazole orange derivatives were screened as “clicked” conjugates in different surrounding DNA sequences. The combination of the (S)-configured DNA anchor and the cyanylated cyanine–styryl dye shows the highest fluorescence light-up effect of 9.2 and a brightness of approximately 11,000 M–1 cm–1. This hybridization sensitivity and fluorescence readout were further developed utilizing electron transfer and energy transfer processes. The combination of the hybridization-sensitive DNA building block with the nucleotide of 5-nitroindole as an electron acceptor and a quencher increases the light-up effect to 20 with the DNA target and to 15 with the RNA target. The fluorescence readout could significantly be enhanced to values between 50 and 360 by the use of energy transfer to a second DNA probe with commercially available dyes, like Cy3.5, Cy5, and Atto590, as energy acceptors at the 5′-end. The latter binary probes shift the fluorescent readout from the range of 500–550 nm to the range of 610–670 nm. The optical properties make these fluorescent DNA probes potentially useful for RNA imaging. Due to the strong light-up effect, they will not require washing procedures and will thus be suitable for live-cell imaging.

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Section: Resultsmentioning

confidence: 99%

Hybridization-Sensitive Fluorescent Probes for DNA and RNA by a Modular “Click” Approach

et al. 2022

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“…To properly assess this result, one has to recall that RCM of 33 comprising a single tert -amine could not be enforced at all with the aid of Grubbs-type ruthenium carbene complexes, even after protonation. Therefore, this example—together with a number of other advanced applications 39 − 44 , 57 , 116 − 126 —may help correct the misperception that high-valent early transition metal catalysts provide (too) few opportunities when working with densely decorated compounds; in any case, it is fair to claim that the newly developed molybdenum alkylidynes with (tripodal) silanolate ligands are distinguished by a remarkable and enabling functional group tolerance.…”

Section: Resultsmentioning

confidence: 99%

A Unified Approach to Polycyclic Alkaloids of the Ingenamine Estate: Total Syntheses of Keramaphidin B, Ingenamine, and Nominal Njaoamine I

et al. 2021

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Many polycyclic marine alkaloids are thought to derive from partly reduced macrocyclic alkylpyridine derivatives via a transannular Diels–Alder reaction that forms their common etheno-bridged diaza-decaline core (“Baldwin–Whitehead hypothesis”). Rather than trying to emulate this biosynthesis pathway, a route to these natural products following purely chemical logic was pursued. Specifically, a Michael/Michael addition cascade provided rapid access to this conspicuous tricyclic scaffold and allowed different handles to be introduced at the bridgehead quarternary center. This flexibility opened opportunities for the formation of the enveloping medium-sized and macrocyclic rings. Ring closing alkyne metathesis (RCAM) proved most reliable and became a recurrent theme en route to keramaphidin B, ingenamine, xestocyclamine A, and nominal njaoamine I (the structure of which had to be corrected in the aftermath of the synthesis). Best results were obtained with molybdenum alkylidyne catalysts endowed with (tripodal) silanolate ligands, which proved fully operative in the presence of tertiary amines, quinoline, and other Lewis basic sites. RCAM was successfully interlinked with macrolactamization, an intricate hydroboration/protonation/alkyl-Suzuki coupling sequence, or ring closing olefin metathesis (RCM) for the closure of the second lateral ring; the use of RCM for the formation of an 11-membered cycle is particularly noteworthy. Equally rare are RCM reactions that leave a pre-existing triple bond untouched, as the standard ruthenium catalysts are usually indiscriminative vis-à-vis the different π-bonds. Of arguably highest significance, however, is the use of two consecutive or even concurrent RCAM reactions en route to nominal njaoamine I as the arguably most complex of the chosen targets.

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“…Polyketides are natural metabolites, having large structural diversity and being renowned for exhibiting a large number of biological activities. Various synthetic strategies have previously been employed for the synthesis of the core structure of these metabolites, involving double Sakurai allylation [123], Mitsunobu reaction [104] and alkyne metathesis [124,125], but these strategies produced a large amount of waste and were not considered appropriate with respect to atom economy. In 2015, Haydl and Breit introduced a new, atom-economical, regioselective strategical procedure for the synthesis of a 16-membered skeleton of clavosolide A in eight steps [126].…”

Section: Synthesis Of Polyketide-based Natural Productmentioning

confidence: 99%

Simmons–Smith Cyclopropanation: A Multifaceted Synthetic Protocol toward the Synthesis of Natural Products and Drugs: A Review

Munir,

Zahoor,

Javed

et al. 2023

Molecules

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Simmons–Smith cyclopropanation is a widely used reaction in organic synthesis for stereospecific conversion of alkenes into cyclopropane. The utility of this reaction can be realized by the fact that the cyclopropane motif is a privileged synthetic intermediate and a core structural unit of many biologically active natural compounds such as terpenoids, alkaloids, nucleosides, amino acids, fatty acids, polyketides and drugs. The modified form of Simmons–Smith cyclopropanation involves the employment of Et2Zn and CH2I2 (Furukawa reagent) toward the total synthesis of a variety of structurally complex natural products that possess broad range of biological activities including anticancer, antimicrobial and antiviral activities. This review aims to provide an intriguing glimpse of the Furukawa-modified Simmons–Smith cyclopropanation, within the year range of 2005 to 2022.

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Self‐Assembly of Disorazole C₁ through a One‐Pot Alkyne Metathesis Homodimerization Strategy

Cited by 33 publications

References 56 publications

Hybridization-Sensitive Fluorescent Probes for DNA and RNA by a Modular “Click” Approach

Hybridization-Sensitive Fluorescent Probes for DNA and RNA by a Modular “Click” Approach

A Unified Approach to Polycyclic Alkaloids of the Ingenamine Estate: Total Syntheses of Keramaphidin B, Ingenamine, and Nominal Njaoamine I

Simmons–Smith Cyclopropanation: A Multifaceted Synthetic Protocol toward the Synthesis of Natural Products and Drugs: A Review

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Self‐Assembly of Disorazole C1 through a One‐Pot Alkyne Metathesis Homodimerization Strategy

Cited by 33 publications

References 56 publications

Hybridization-Sensitive Fluorescent Probes for DNA and RNA by a Modular “Click” Approach

Hybridization-Sensitive Fluorescent Probes for DNA and RNA by a Modular “Click” Approach

A Unified Approach to Polycyclic Alkaloids of the Ingenamine Estate: Total Syntheses of Keramaphidin B, Ingenamine, and Nominal Njaoamine I

Simmons–Smith Cyclopropanation: A Multifaceted Synthetic Protocol toward the Synthesis of Natural Products and Drugs: A Review

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Self‐Assembly of Disorazole C₁ through a One‐Pot Alkyne Metathesis Homodimerization Strategy