In studying the evolution of organic chemistry and grasping its essence, one comes quickly to the conclusion that no other type of reaction plays as large a role in shaping this domain of science than carbon-carbon bond-forming reactions. The Grignard, Diels-Alder, and Wittig reactions are but three prominent examples of such processes, and are among those which have undeniably exercised decisive roles in the last century in the emergence of chemical synthesis as we know it today. In the last quarter of the 20th century, a new family of carbon-carbon bond-forming reactions based on transition-metal catalysts evolved as powerful tools in synthesis. Among them, the palladium-catalyzed cross-coupling reactions are the most prominent. In this Review, highlights of a number of selected syntheses are discussed. The examples chosen demonstrate the enormous power of these processes in the art of total synthesis and underscore their future potential in chemical synthesis.

The design and implementation of cascade reactions is a challenging facet of organic chemistry, yet one that can impart striking novelty, elegance, and efficiency to synthetic strategies. The application of cascade reactions to natural products synthesis represents a particularly demanding task, but the results can be both stunning and instructive. This Review highlights selected examples of cascade reactions in total synthesis, with particular emphasis on recent applications therein. The examples discussed herein illustrate the power of these processes in the construction of complex molecules and underscore their future potential in chemical synthesis.

With the exception of palladium-catalyzed cross-couplings, no other group of reactions has had such a profound impact on the formation of carbon-carbon bonds and the art of total synthesis in the last quarter of a century than the metathesis reactions of olefins, enynes, and alkynes. Herein, we highlight a number of selected examples of total syntheses in which such processes played a crucial role and which imparted to these endeavors certain elements of novelty, elegance, and efficiency. Judging from their short but impressive history, the influence of these reactions in chemical synthesis is destined to increase.

Wenn man die Entwicklung der organischen Chemie betrachtet, kommt man schnell zu dem Schluss, dass kein Reaktionstyp dieses Gebiet in vergleichbarer Weise geprägt hat wie die Kohlenstoff‐Kohlenstoff‐Kupplungen. Grignard‐, Diels‐Alder‐ und Wittig‐Reaktionen sind nur drei herausragende Beispiele für solche Prozesse, die im vergangenen Jahrhundert zweifellos entscheidend am Aufstieg der chemischen Synthese beteiligt waren. Im letzten Viertel des 20. Jahrhunderts bereicherte eine neue Familie von leistungsfähigen Reaktionen zur Knüpfung von Kohlenstoff‐Kohlenstoff‐Bindungen das Repertoire der Synthesechemie: die übergangsmetallkatalysierten Reaktionen, allen voran die palladiumkatalysierten Kreuzkupplungen. In diesem Aufsatz werden Auszüge aus einer Reihe von ausgewählten Synthesen diskutiert. Die Beispiele sollen die enorme Leistungsfähigkeit dieser Prozesse in der Kunst der Totalsynthese aufzeigen und ihr Potenzial für zukünftige chemische Synthesen unterstreichen.

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Process development of the synthesis of the orally active poly(ADP-ribose)polymerase inhibitor niraparib is described. Two new asymmetric routes are reported, which converge on a high-yielding, regioselective, copper-catalyzed N-arylation of an indazole derivative as the late-stage fragment coupling step. Novel transaminase-mediated dynamic kinetic resolutions of racemic aldehyde surrogates provided enantioselective syntheses of the 3-aryl-piperidine coupling partner. Conversion of the C–N cross-coupling product to the final API was achieved by deprotection and salt metathesis to isolate the desired crystalline salt form.

Die Entwicklung und Umsetzung von Kaskadenreaktionen hat zu beachtlichen neuartigen, eleganten und effizienten Synthesestrategien geführt. Als besonders anspruchsvoll erwies sich die Anwendung von Kaskadenreaktionen in der Naturstoffsynthese, doch gerade hier winken verblüffende und zugleich aufschlussreiche Ergebnisse als Belohnung. In diesem Aufsatz werden ausgewählte Kaskadenreaktionen in der Totalsynthese erläutert, wobei neuere Anwendungen besonders hervorgehoben werden. Die erörterten Beispiele sollen die Leistungsfähigkeit dieser Prozesse beim Aufbau von komplexen Molekülstrukturen veranschaulichen und ihr Potenzial für zukünftige chemische Synthesen verdeutlichen.

In this paper, we report the development of different synthetic routes to MK-7246 (1) designed by the Process Chemistry group. The syntheses were initially designed as an enabling tool for Medicinal Chemistry colleagues in order to rapidly explore structure-activity relationships (SAR) and to procure the first milligrams of diverse target molecules for in vitro evaluation. The initial aziridine opening/cyclodehydration strategy was also directly amenable to the first GMP deliveries of MK-7246 (1), streamlining the transition from milligram to kilogram-scale production needed to support early preclinical and clinical evaluation of this compound. Subsequently a more scalable and cost-effective manufacturing route to MK-7246 (1) was engineered. Highlights of the manufacturing route include an Ir-catalyzed intramolecular N-H insertion of sulfoxonium ylide 41 and conversion of ketone 32 to amine 31 in a single step with excellent enantioselectivity through a transaminase process. Reactions such as these illustrate the enabling impact and efficiency gains that innovative developments in chemo- and biocatalysis can have on the synthesis of pharmaceutically relevant target molecules.