Synthetic studies on arene-olepin cycloadditions-VII:1 a three-step total synthesis of (±)-silphinene

Wender, Paul A.; Ternansky, Robert J.

doi:10.1016/s0040-4039(00)98120-6

Cited by 79 publications

(31 citation statements)

References 10 publications

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“…Mit dieser Strategie wurden auch (À)-Penifulvin B und (À)-Penifulvin C totalsynthetisch hergestellt. [466] Zu den durch eine meta-Photocycloaddition hergestellten angularen Triquinanen zählen (AE )-Isocomen (191, Schema 52), [467] (AE )-Silphinen, [468] (AE )-Silphiperfol-6-en, [469] (AE )-7bH-Silphiperfol-5-en, [469] (AE )-Retigeransäure, [470] (AE )-Subergorginsäure [471] und (AE )-Crinipellin B.…”

Section: Meta-photocycloadditionunclassified

Photochemische Reaktionen als Schlüsselschritte in der Naturstoffsynthese

2011

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Photochemische Reaktionen bereichern in signifikanter Weise das Repertoire zur Knüpfung von Kohlenstoff‐Kohlenstoff‐Bindungen und machen ungewöhnliche, auf herkömmlichem Weg nicht erhältliche Molekülgerüste zugänglich. In diesem Aufsatz werden die wichtigsten Umsetzungen der Photochemie vorgestellt, die auf breiter Front Einzug in die Naturstoffsynthese gehalten haben. Beispielhaft werden einzelne Totalsynthesen diskutiert, wobei besonderes Augenmerk auf den photochemischen Schlüsselschritt sowie dessen Stereoselektivität gerichtet ist. Dabei wird das photochemisch erzeugte Molekül in Relation zur Struktur des Naturstoffs gebracht, und Folgereaktionen werden, wo notwendig, illustriert und klassifiziert.

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Section: Meta-photocycloadditionunclassified

Photochemische Reaktionen als Schlüsselschritte in der Naturstoffsynthese

2011

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“…Initial interest in {[RhCl(CO) 2 ] 2 } was prompted, in part, by the expectation that it would be less sterically encumbered than Wilkinson's catalyst. 3 ]/silver triflate resulted only in the formation of complex product mixtures. In remarkable contrast, when this same substrate was treated with 5 mol% {[RhCl(CO) 2 ] 2 } for 20 min in toluene at 110 8C, the [5+2] cycloadduct 80 was obtained in 80% yield.…”

Section: Other Catalyst Systemsmentioning

confidence: 99%

“…New reactions give rise to new synthetic strategies, which in turn allow for more step-economical, if not ideal, approaches to molecules of interest [2]. The synthesis of silphinene (Scheme 13.1) illustrates how a target, requiring typically ten to twenty steps, can be prepared in only three steps based on a new strategy inspired by a new reaction, the arenealkene cycloaddition [3]. New reactions also enable more rapid and efficient access to known and, more importantly, structurally novel chemical libraries.…”

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confidence: 99%

Rhodium(I)‐Catalyzed [5+2], [6+2], and [5+2+1] Cycloadditions: New Reactions for Organic Synthesis

Wender

Gamber

Williams

2005

Modern Rhodium‐Catalyzed Organic Reactions

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IntroductionOrganic synthesis has played a major role in the advancement of modern science and technology by enabling the preparation of natural and designed targets of chemical, biological, medicinal, environmental, and materials importance [1]. This progress and its continuation toward products of even greater value are unique consequences of the design or discovery and development of fundamentally new reactions. New reactions give rise to new synthetic strategies, which in turn allow for more step-economical, if not ideal, approaches to molecules of interest [2]. The synthesis of silphinene (Scheme 13.1) illustrates how a target, requiring typically ten to twenty steps, can be prepared in only three steps based on a new strategy inspired by a new reaction, the arenealkene cycloaddition [3]. New reactions also enable more rapid and efficient access to known and, more importantly, structurally novel chemical libraries. New reactions can also provide benefits in safety, cost, time, resource utilization, and environmental impact, while simultaneously introducing new mechanisms and opportunities for achieving synthetic selectivity (chemo-, regio-, stereo-, and enantioselectivity).Among the classes of new reactions, cycloadditions are of unique value for increasing molecular complexity and thereby achieving step brevity [4]. They allow for the assembly of complex ring systems in a convergent and often selective fashion, generally from simple, readily available building blocks. The Diels-Alder cycloaddition (Scheme 13.2) [5] is illustrative of the enormous utility of such reactions in synthesis, providing a cycloadduct with up to four stereogenic centers in one step. This process has figured prominently in the synthesis of six-membered ring systems found in a wide array of molecules of theoretical, medicinal, and materials value. hm Scheme 13.1 New reactions and step economy: a three-step total synthesis of silphinene.13 Rhodium(I)-Catalyzed [5+2], [6+2], and [5+2+1] Cycloadditions 264 Scheme 13.2 The Diels-Alder reaction: convergency and complexity increase to favor step economy. Scheme 13.3 Representative natural products incorporating medium-sized rings. p p 13.2 Cycloaddition Approaches to Seven-Membered Rings 265 Scheme 13.4 Metal catalysis enables forbidden or difficult noncatalyzed reactions: [4+4] and [4+2] reactions of dienes. 13.3 Design of a Transition Metal-Catalyzed [5+2] Cycloaddition of Vinylcyclopropanes and p-Systems 267 Scheme 13.7 The [5+2] cycloaddition: a conceptual homolog of the Diels-Alder reaction. p p p r p 13 Rhodium(I)-Catalyzed [5+2], [6+2], and [5+2+1] Cycloadditions 268 Scheme 13.8 Metal-catalyzed VCP isomerization and the design of a new reaction. Scheme 13.9 Strain-driven cleavage of metal carbinyl cyclopropanes. 13.6 Cycloaddition Approaches for Eight-Membered Ring Synthesis 291 Scheme 13.17 The first examples of hetero-[5+2] cycloadditions. 13 Rhodium(I)-Catalyzed [5+2], [6+2], and [5+2+1] Cycloadditions 292 Scheme 13.18 Representative examples of transition metal-mediated cycloaddi...

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“…The message here was clear: if one could learn how to make molecules more quickly and efficiently one would have more time to spend on their study. I knew too little then to understand the broader ramifications of this perception but, as partly elaborated herein, it has indeed been a career long theme taking the form some years later of “step and time economy” and “function oriented synthesis” directed at “the ideal synthesis”, 3 a goal we defined in 1985 in a form that most would agree with today: “ ideal syntheses [are] those in which the target molecule is assembled from readily available starting materials in one simple, safe, economical, and efficient operation.” 4 …”

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confidence: 99%

“…This concept is evident in the step economy of subsequent total syntheses of numerous other natural as well as non-natural products based on the arene-alkene photocycloaddition, including a rather remarkable 3-step synthesis of the triquinane silphinene ( 58 , Scheme 13) 43 and a 3-step synthesis of novel-fenestranes 44 . The silphinene synthesis serves to reinforce and extend selectivity predictions made in the cedrene synthesis and clearly provides another demonstration of the striking correlation of complexity increase and step economy: the greater the increase in target relevant complexity per step, the shorter the synthesis.…”

mentioning

confidence: 99%