AggarwalLab retweeted
Appearing today as an Accelerated Article Preview publication in @Nature :nature.com/articles/s41586-0…
Making C-glycosides SWEET and simple! Today in @ChemRxiv we disclose (chemrxiv.org/doi/full/10.264…), in collaboration with @GroupAggarwal, an incredibly easy way to achieve radical functionalization of sugars. In this video (youtu.be/Fqdbgmx7zEI), a two-step synthesis of the billion dollar drug Dapagliflozin is achieved using household vinegar and dextrose powder from the local supplement store.
High Level Summary:
The work addresses a longstanding challenge in carbohydrate chemistry: the efficient, scalable, and stereocontrolled synthesis of C-aryl glycosides directly from unprotected native sugars. C-Aryl glycosides form the core pharmacophore of the SGLT2 inhibitors (dapagliflozin, canagliflozin, empagliflozin, and related agents), which are frontline therapies for type 2 diabetes and represent one of the highest-grossing classes of small-molecule drugs.
Conventional synthetic routes to these molecules generally require extensive protecting-group manipulations, multi-step activation of glycosyl donors, or organometallic additions under demanding conditions. Recent advances in radical and transition-metal-catalyzed cross-couplings have improved access, yet most approaches still depend on protected precursors, specialized reagents, or protocols that are difficult to scale.
We report a practical alternative based on glycosyl sulfonyl hydrazides—stable, crystalline radical precursors that are prepared in a single step from unprotected sugars by treatment with tosylhydrazine in acetic acid, followed by simple crystallization. These hydrazides undergo redox-neutral nickel-catalyzed radical cross-coupling with aryl iodides or bromides under mild conditions (70 °C, DMSO, tetramethylguanidine as base). The reaction requires no external oxidant or reductant, no photocatalyst, and no organotin species. In glucose-derived systems the coupling typically delivers high β-selectivity (>19:1 in many cases), an outcome that appears to depend on hydrogen-bonding interactions between tetramethylguanidine and the free hydroxyl groups.
The main findings are as follows:
All five FDA-approved SGLT2 inhibitors, as well as several clinical candidates, can be prepared in a single coupling step from the corresponding glycohydrazide.
Decagram-scale synthesis of dapagliflozin was demonstrated starting from commercial dextrose; the product was isolated by aqueous workup and recrystallization (no column chromatography required at this scale).
Di- and trisaccharides (lactose, cellobiose, maltose, maltotriose) couple directly to give aryl-linked oligosaccharides.
Several natural products and medicinally relevant structures (salmochelin-SX, neopetrosin C, the tryptophan-mannose conjugate, and a ribose-derived IMPDH inhibitor) that previously required 9–20 steps or costly reagents are now accessible in 1–4 steps with good stereocontrol.
The platform extends to non-anomeric C–C bond formation at positions C2–C6 on glucose and ribose scaffolds, providing the first systematic exploration of radical diversification across these positions.
Stereoretentive radical cross-coupling, using configurationally pure hydrazides, enables programmable delivery of either α- or β-anomers, overriding inherent substrate biases and providing access to stereoisomers not previously obtainable by radical methods.
The chemistry builds on our earlier development of sulfonyl hydrazide-based redox-neutral cross-coupling and stereoretentive radical arylation, here adapted and optimized for carbohydrate substrates. The method is operationally straightforward, uses inexpensive reagents and starting materials, and eliminates protecting-group strategies.
AggarwalLab retweeted
Now online & open access:
Article by Malcolm R. P. George, Craig P. Butts, Varinder K. Aggarwal & co-workers @AggarwalLab
The combination of synthesis and ultra-high-resolution NMR spectroscopy reveals the correct structure of caylobolide A
nature.com/articles/s44160-0…
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Come and hear the latest from our star-studded speakers at this years BSM. Deadline for registration is 28th March. Please re-tweet.
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Interesting to discover that organozinc reagents react with inversion of configuration with pi-allyl iridum complexes, unlike other electrophiles where they react with retention. Congratulations to Hong Cheng for his meticulous studies. @J_A_C_S @BristolChem @AggarwalLab
Iridium-Catalyzed Stereocontrolled C(sp3)–C(sp3) Cross-Coupling of Boronic Esters and Allylic Carbonates Enabled by Boron-to-Zinc Transmetalation | Journal of the American Chemical Society @BristolUni @BristolChem @VarinderAggar11 @TotalSyntheses pubs.acs.org/doi/10.1021/jac…
AggarwalLab retweeted
Congratulations @HettyWalker2 on winning the poster competition @UoBPPN . Very proud of your work @AggarwalLab @HersIngeborg @tocris @BristolChem
Congratulations to @HettyWalker2 for winning the best presentation prize at the @UoBPPN postgraduate away day. 🎉 Exciting work on design and application of FAK PROTACs in human platelets. @Tocris #TPD @HersIngeborg @VarinderAggar11
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This week we were delighted to have Professor @GloriusFrank to receive the 2024 Bristol-Syngenta Award. Frank gave his plenary lecture titled 'On Discovery and Sensitivity in (Photo)Catalysis', followed by a second lecture on career and science. Thank you Frank for your visit!
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Special Collection on Boron Chemistry (Hajime Ito and co-workers) @AggarwalLab @haj19932469 @BristolUni @ICReDDconnect onlinelibrary.wiley.com/doi/…
AggarwalLab retweeted
And to close out our eclectic day of research, perhaps one of the more unorthodox slides!
Professor Francis Arnold from California Institute of Technology presents the Vertex Lecture, titled: 'Innovation by Evolution: Bringing New Chemistry to Life'.
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Heading the Syngenta Lecture we had Professor Martin Burke from the University of Illinois.
An illuminating conversation which helped us 'Imagine a world where everyone can make molecules.'
AggarwalLab retweeted
We then had Professor Kimoon Kim from Pohang University of Science and Technology present a fascinating talk.
This was titled 'Spatiotemporal Control of Chemical Reactions with Sound' and was just as riveting as those that preceded.
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Following on from this we had Professor Tehshik Yoon from the University of Wisconsin-Madison presenting the Novartis Lecture.
Another engaging talk, this was titled 'Stereocontrol in Photochemical Synthesis'.
AggarwalLab retweeted
Professor Véronique Gourverner, from the University of Oxford, followed, giving a talk on behalf of Astrazeneca.
Titled 'Rethinking Fluorine Chemistry with Global Challenges in Mind', it was a fascinating listen.
AggarwalLab retweeted
Another successful Bristol Synthesis Meeting: check! ✅
Have a scan of this thread to see some highlights from this year's assembly - a vast range of intriguing talks, if we do say so ourselves! 🧪
AggarwalLab retweeted
We are excited to announce the winners of the CSC Research Impact Awards 2023 🏆
Congratulations to #Commonwealth Alumni @nii_cornelius, Maryam Bashir, and @DrDammalaIITJ whose research is pushing the frontiers of knowledge and impact across the world.
bit.ly/3fVXRCk
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Explore one of our #MostRead papers this year ⚡
🔬 "Copper-Mediated Dehydrogenative C(sp3)–H Borylation of Alkanes" 📝 by Ruocheng Sang, Wangyujing Han, Hanwen Zhang, Carla M. Saunders, Adam Noble, and Varinder K. Aggarwal @AggarwalLab @RuochengS
🔓 go.acs.org/7mE
AggarwalLab retweeted
Stereospecific Conversion of Boronic Esters into Enones using Methoxyallene: Application in the Total Synthesis of 10-Deoxymethynolide (@AggarwalLab, @VarinderAggar11): onlinelibrary.wiley.com/doi/… (@angew_chem).
AggarwalLab retweeted
Amazing to see that this is one of the most downloaded papers on the @J_A_C_S website of 2023. Congrats to Ruocheng, Wangyujing, Hanwen and Adam. @BristolChem @AggarwalLab
pubs.acs.org/action/showMost…
Our latest work, out now in @J_A_C_S, investigates a copper mediated borylation of C(sp³)-H bonds. Great work by Ruocheng, Wangyujing, and Hanwen! pubs.acs.org/doi/10.1021/jac…
AggarwalLab retweeted
I very much enjoyed attending the International Symposium on Synthesis and Catalysis 2023, held in Évora, Portugal last week. There was so much inspiring chemistry on display. I was also pleasantly surprised to be awarded the prize for best oral communication! #ISySyCat 🇵🇹 – at Bristol, England
AggarwalLab retweeted
📈This highly accessed open access article investigates the de novo synthesis of dihydrobenzofurans and indolines, and the application of this work in the asymmetric synthesis of the antiplatelet drug beraprost. @AggarwalLab @BristolChem
Read it here ➡️ go.acs.org/5sQ
AggarwalLab retweeted
Conformationally Controlled sp3-Hydrocarbon-Based alpha-Helix Mimetics (Varinder K. Aggarwal and co-workers) @AggarwalLab @BristolChem #openaccess onlinelibrary.wiley.com/doi/…


































