Cyclopropyl Building Blocks in Organic Synthesis. Part 77. A New Highly Efficient Three‐Component Domino Heck—Diels—Alder Reaction with Bicyclopropylidene: Rapid Access to Spiro[2,5]oct‐4‐ene Derivatives.

Nueske, Hanno; Braese, Stefan; Kozhushkov, Sergei I.; Noltemeyer, Mathias; Es‐Sayed, Mazen; Meijere, Armin de

doi:10.1002/chin.200241064

Cited by 2 publications

(2 citation statements)

References 4 publications

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“…This conclusion can also be kept if one considers the pathway of TS2b→IN4b→TS3b for model reaction 1 because the strain release makes TS2b easier. Similar reactions driven by strain release from MCPs include Cope rearrangement of CP-capped 1,5-dienes by Tantillo and Gagné, the Diels–Alder reaction of CP-capped dienes with alkenes, and our recent [4 + 2 + 1] reaction of CP-capped diene-ynes/diene-enes and CO …”

Section: Resultsmentioning

confidence: 80%

Rh-Catalyzed [4 + 1] Reaction of Cyclopropyl-Capped Dienes (but not Common Dienes) and Carbon Monoxide: Reaction Development and Mechanistic Study

Yang,

Li,

Zhu

et al. 2023

J. Am. Chem. Soc.

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reaction of dienes and carbon monoxide (CO) is the most straightforward and easily envisioned cyclization for the synthesis of fivemembered carbocycles, which are ubiquitously found in natural products and functional molecules. Unfortunately, no test of this reaction was reported, and consequently, chemists do not know whether such kind of reaction works or not. Herein, we report that the [4 + 1] reaction of common dienes and CO cannot work, at least under the catalysis of [Rh(cod)Cl] 2 . However, using cyclopropyl-capped dienes (also named allylidenecyclopropanes) as substrates, the corresponding [4 + 1] reaction with CO proceeds smoothly in the presence of [Rh(cod)Cl] 2 . This [4 + 1] reaction, with a broad scope, provides efficient access to five-membered carbocyclic compounds of spiro[2.4]hept-6-en-4-ones. The [4 + 1] cycloadducts can be further transformed into other molecules by using the unique chemistry of cyclopropyl groups present in these molecules. The mechanism of this [4 + 1] reaction has been investigated by quantum chemical calculations, uncovering that cyclopropyl-capped dienes are strained dienes and the oxidative cyclization step in the [4 + 1] catalytic cycle can release this (angular) strain both kinetically and thermodynamically. The strain release in this step then propagates to all followed CO coordination/CO insertion/reductive elimination steps in the [4 + 1] catalytic cycle, helping the realization of this cycloaddition reaction. In contrast, common dienes (including cyclobutyl-capped dienes) do not have such advantages and their [4 + 1] reaction suffers from energy penalty in all steps involved in the [4 + 1] catalytic cycle. The reactivity of ene-allenes for the [4 + 1] reaction with CO is also discussed.

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Section: Resultsmentioning

confidence: 80%

Rh-Catalyzed [4 + 1] Reaction of Cyclopropyl-Capped Dienes (but not Common Dienes) and Carbon Monoxide: Reaction Development and Mechanistic Study

Yang,

Li,

Zhu

et al. 2023

J. Am. Chem. Soc.

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“…We initially tried to use cyclopropyl-capped dienes (CP-capped dienes in short) , and CO for the synthesis of eight-membered carbocycles, hypothesizing that the cyclopropyl (CP) group in the substrates can be cleaved, as many reactions of methylenecyclopropane (MCP) did . Instead of CP cleavage, we found a [4 + 2 + 1] reaction of CP-capped diene-ynes/diene-enes with CO under the catalysis of rhodium, which is present in this paper (Scheme c).…”

Section: Introductionmentioning

confidence: 86%

Strain-Release-Controlled [4 + 2 + 1] Reaction of Cyclopropyl-Capped Diene-ynes/Diene-enes and Carbon Monoxide Catalyzed by Rhodium

Yang

Zhou

et al. 2023

J. Am. Chem. Soc.

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Achieving transition-metal-catalyzed reactions of diene-ynes/diene-enes and carbon monoxide (CO) to deliver [4 + 2 + 1] cycloadducts, rather than the kinetically favored [2 + 2 + 1] products, is challenging. Here, we report that this can be solved by adding a cyclopropyl (CP) cap to the diene moiety of the original substrates. The resulting CP-capped diene-ynes/diene-enes can react with CO under Rh catalysis to give [4 + 2 + 1] cycloadducts exclusively without forming [2 + 2 + 1] products. This reaction has a broad scope and can be used to synthesize useful 5/7 bicycles with a CP moiety. Of the same importance, the CP moiety in the [4 + 2 + 1] cycloadducts can act as an intermediate group for further transformations so that other challenging bicyclic 5/7 and tricyclic 5/ 7/5, 5/7/6, and 5/7/7 skeletons, some of which are widely found in natural products, can be accessed. The mechanism of this [4 + 2 + 1] reaction has been investigated by quantum chemical calculations, and the role of the CP group in avoiding the possible side [2 + 2 + 1] reaction has been identified, showing that the [4 + 2 + 1] is controlled by releasing the ring strain in the methylenecyclopropyl (MCP) group (about 7 kcal/mol) in the CP-capped dienes.

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Cyclopropyl Building Blocks in Organic Synthesis. Part 77. A New Highly Efficient Three‐Component Domino Heck—Diels—Alder Reaction with Bicyclopropylidene: Rapid Access to Spiro[2,5]oct‐4‐ene Derivatives.

Cited by 2 publications

References 4 publications

Rh-Catalyzed [4 + 1] Reaction of Cyclopropyl-Capped Dienes (but not Common Dienes) and Carbon Monoxide: Reaction Development and Mechanistic Study

Rh-Catalyzed [4 + 1] Reaction of Cyclopropyl-Capped Dienes (but not Common Dienes) and Carbon Monoxide: Reaction Development and Mechanistic Study

Strain-Release-Controlled [4 + 2 + 1] Reaction of Cyclopropyl-Capped Diene-ynes/Diene-enes and Carbon Monoxide Catalyzed by Rhodium

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