데이비드 첸 교수

In this tutorial review, recent advances in the synthesis of cyclopropane-containing natural products are discussed, highlighting the application of novel synthetic methodologies and innovative synthetic strategies in the construction of highly functionalized cyclopropanes. The examples showcased herein aim to inspire students and practitioners of organic synthesis to seek further advances in the chemical synthesis of cyclopropanes, both in the context of target-oriented syntheses and method dev

The recent advent of transition-metal mediated C-H activation is revolutionizing the synthetic field and gradually infusing a "C-H activation mind-set" in both students and practitioners of organic synthesis. As a powerful testament of this emerging synthetic tool, applications of C-H activation in the context of total synthesis of complex natural products are beginning to blossom. Herein, recently completed total syntheses showcasing creative and ingenious incorporation of C-H activation as a s

With their fascinating biological profiles and stunningly complex molecular architectures, the polycyclic polyprenylated acylphloroglucinols (PPAPs) have long provided a fertile playing field for synthetic organic chemists. In particular, the recent advent of innovative synthetic methods and strategies together with C-C bond-forming reactions and asymmetric catalysis have revitalized this field tremendously. Consequently, PPAP targets which once seemed beyond reach have now been synthesized. Thi

Marine engineering: A modular strategy featuring an intramolecular 1,4-addition/aldol/dehydration cascade sequence (see scheme; TBS=tert-butyldimethylsilyl) has enabled the total synthesis of cortistatin A, a potent anti-angiogenic marine natural product. This flexible route offers access to other members of the cortistatin family, both natural and designed.

In the palm of your hand: Total syntheses of the originally proposed and revised structures of the marine antitumor agent palmerolide A (see picture, originally proposed structure had opposite configurations at the positions indicated in red) were accomplished through a modular strategy that features a ring-closing metathesis to stereoselectively form the C8C9 bond and concurrently form the macrocycle.

Fatty acid biosynthesis is a promising novel antibiotic target. Two inhibitors of fatty acid biosynthesis, platencin and platensimycin, were recently discovered and their molecular targets identified. Numerous structure-activity relationship studies for both platencin and platensimycin are currently being undertaken. We established a proteomic signature for fatty acid biosynthesis inhibition in Bacillus subtilis using platencin, platensimycin, cerulenin, and triclosan. The induced proteins, FabH

Beat the bugs: Total syntheses of the thiopeptide antibiotics GE2270A (XY=CH2CH) and GE2270T (XY=CHC) have been accomplished. The modular approach featured a hetero-Diels–Alder dimerization (A) to construct the trithiazolyl pyridine domain, and highly regioselective macrolactamizations (B) to furnish the macrocyclic core.

Die hoch gespannte einzigartige Molekülstruktur und die potenzielle tumortherapeutische Wirkung von Diazonamid A (1) machen diesen Naturstoff zu einem attraktiven Syntheseziel. Zu den Schlüsselschritten dieser Totalsynthese von 1 zählen die neuartige SmI2-gestützte Ringöffnungs-Sequenz und die ungewöhnliche Oxidation eines Indolins zu einem Oxindol in Gegenwart von Pd(OH)2/C.

In the long lasting battle against cancer, Nature sometimes gives a helping hand to researchers to find new drugs for the treatment of diseases and improvement of patients' well-being. Englerin A has emerged as a promising anticancer candidate as well as being an exciting synthetic challenge for organic chemists. This focus review summarizes the total syntheses reported to date and the synthetic approaches toward analogues of this fascinating natural product.

Two strategies toward the total synthesis of maoecrystal V (1) culminating in the construction of core structures 2 and 3 are described.

Enticing structures: The formal syntheses of 1 and 2 were accomplished by using a cascade strategy involving an enyne cycloisomerization reaction and an intramolecular Diels–Alder reaction starting from 3. The resulting 4 underwent a late-stage ring contraction to enable the preparation of a reported advanced intermediate, thereby constituting a formal synthesis of the structurally intriguing title compounds. Detailed facts of importance to specialist readers are published as ”Supporting Informa

Get to the core: The synthesis of an advanced structure of the recently reported cytotoxic diterpenoid maoecrystal V (1) has been accomplished. The key carbon–carbon bond-forming events feature an intramolecular Diels–Alder reaction, a cyclopropanation/reductive cleavage sequence, and an intramolecular alkylative lactonization reaction. Furthermore, a hydroxyl-directed hydrogenation was implemented to cast the desired C5 stereochemistry. Detailed facts of importance to specialist readers are pub

Here we report a total synthesis of the pharmacologically significant morphinan alkaloid, oxycodone. The centerpiece of the developed strategy features the first application of the Rovis desymmetrization of peroxyquinol in target-oriented total synthesis to access an optically active phenanthrene framework shared by the morphinans. A Stork-Ueno radical cyclization under photoredox conditions installed the all-carbon quaternary stereocenter, and a late-stage reductive detosylation with concomitan

Problem gelöst: Die Totalsynthese von Haplophytin (1) gelang durch eine konvergente Strategie mit modernsten Synthesemethoden. Schlüsselschritte sind eine durch hypervalentes Iod vermittelte oxidative Kupplung, eine oxidative Semipinakol-Umlagerung, eine Suzuki-Miyaura-Kupplung und eine radikalische Cyclisierung.

Here we report asymmetric total syntheses of communesin F and a putative member of the communesin family of bis-aminal alkaloid natural products. The successful strategy featured the invention of an asymmetric organocatalytic reaction to unify two oxindole subunits, a Ti(Oⁱ Pr)₄ -mediated dehydrative skeletal rearrangement, and a late-stage Pd(OAc)₂ -catalyzed directed CH-alkenylation reaction. Collectively, the synthetic technologies disclosed herein enabled the