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.

Palladium-catalyzed cross-coupling reactions in total synthesis.

Metal-Mediated Synthesis of Medium-Sized Rings

Wenn man die Entwicklung der organischen Chemie betrachtet, kommt man schnell zu dem Schluss, dass kein Reaktionstyp dieses Gebiet in vergleichbarer Weise gepragt hat wie die Kohlenstoff-Kohlenstoff-Kupplungen. Grignard-, Diels-Alder- und Wittig-Reaktionen sind nur drei herausragende Beispiele fur 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 leistungsfahigen Reaktionen zur Knupfung von Kohlenstoff-Kohlenstoff-Bindungen das Repertoire der Synthesechemie: die ubergangsmetallkatalysierten Reaktionen, allen voran die palladiumkatalysierten Kreuzkupplungen. In diesem Aufsatz werden Auszuge aus einer Reihe von ausgewahlten Synthesen diskutiert. Die Beispiele sollen die enorme Leistungsfahigkeit dieser Prozesse in der Kunst der Totalsynthese aufzeigen und ihr Potenzial fur zukunftige chemische Synthesen unterstreichen.

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Palladiumkatalysierte Kreuzkupplungen in der Totalsynthese

A review, cyclization reactions in natural product synthesis of 4-9 membered and larger rings were discussed. [on SciFinder (R)]

Samarium(II)-iodide-mediated cyclizations in natural product synthesis.

Twenty-five years of organic chemistry with diiodosamarium: an overview

Baccatin III was efficiently synthesized from the BC ring system of Taxol,2α,10β-dibenzyloxy-11β-(t-butyldimethylsil-oxy)-7β-hydroxy-1α-(4-methoxybenzyloxy)-8β,15,15-trimethyl-4-methylene-trans-bic...

A new method for the synthesis of baccatin iii

Asymmetric Total Synthesis of TaxolR

Optically active novel taxoids were efficiently synthesized from 8-membered ring compound 3 by successive constructions of BC and ABC ring systems via each intramolecular aldol and intramolecular pinacol coupling reactions.

An Asymmetric Synthesis of the ABC Ring System of 8-Demethyltaxoids from Optically Active 8-Membered Ring Compound via Intramolecular Aldol and Pinacol Coupling Reactions

Optically active 2α,10β-dibenzyloxy-11β-(t-butyldimethylsiloxy)-7β-hydroxy-1α-(4-methoxybenzyloxy)–8β,15,15-trimethyl-4-methylene-trans-bicyclo[6.4.0]dodecan-9-one 2 that corresponds to BC ring system of Taxol was prepared from 8-membered ring enone 3 in high yield via stereoselctive Michael addition and successive intramolecular aldol cyclization. The above 8-membered ring enone 3 was synthesized from the linear optically active polyoxy-compound 4 by SmI2-mediated intramolecular aldol cyclization.

Stereocontrolled Synthesis of the BC Ring System of Taxol

Optically active 1α-allyl-1β,11β-benzylidenedioxy-2α,10β-bis(benzyloxy)-7β,9β-isopropylidenedioxy-8α,12,12-trimethyl-4-methylenebicyclo[6.4.0]dodecane (2)1 which corresponds to BC ring system of 8-epitaxoids was prepared in high yield form ketoaldehyde 8 via intramolecular aldol cyclization and succesive stereoselective methylation reactions. The ketoaldehyde 8 was synthesized from 8-membered ring compound 3 by stereoselective Michael addition using higher-order cuprate.

Hiroki Sakoh

Papers

A new method for the synthesis of baccatin iii

Asymmetric Total Synthesis of TaxolR

An Asymmetric Synthesis of the ABC Ring System of 8-Demethyltaxoids from Optically Active 8-Membered Ring Compound via Intramolecular Aldol and Pinacol Coupling Reactions

Stereocontrolled Synthesis of the BC Ring System of Taxol

An Asymmetric Synthesis of the BC Ring System of 8-Epitaxoids by Way of Intramolecular Aldol and Successive Stereoselective Methylation Reactions