Catalytic Diastereoselective Synthesis of Diquinanes from Acyclic Precursors.

Wang, Jian‐Cheng; Ng, Sze‐Sze; Krische, Michael J.

doi:10.1002/chin.200332057

Cited by 104 publications

(4 citation statements)

References 2 publications

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“…To solve the regioselectivity issue of Lu's [3 + 2] annulation, Krische designed a series of elaborate tethered enone−ynoate systems that undergo facile intramolecular [3 + 2] annulations to generate functionalized diquinanes. 283 A polar solvent (e.g., ethyl acetate) was beneficial for these transformations, giving good yields of the diquinanes. The reaction proceeded smoothly for aromatic, heteroaromatic, and aliphatic enone− ynoate systems (Scheme 211).…”

Section: Phosphine Catalysis Of Allenes With Electrophilesmentioning

confidence: 99%

Phosphine Organocatalysis

et al. 2018

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The hallmark of nucleophilic phosphine catalysis is the initial nucleophilic addition of a phosphine to an electrophilic starting material, producing a reactive zwitterionic intermediate, generally under mild conditions. In this Review, we classify nucleophilic phosphine catalysis reactions in terms of their electrophilic components. In the majority of cases, these electrophiles possess carbon–carbon multiple bonds: alkenes (section 2), allenes (section 3), alkynes (section 4), and Morita–Baylis–Hillman (MBH) alcohol derivatives (MBHADs; section 5). Within each of these sections, the reactions are compiled based on the nature of the second starting material—nucleophiles, dinucleophiles, electrophiles, and electrophile–nucleophiles. Nucleophilic phosphine catalysis reactions that occur via the initial addition to starting materials that do not possess carbon–carbon multiple bonds are collated in section 6. Although not catalytic in the phosphine, the formation of ylides through the nucleophilic addition of phosphines to carbon–carbon multiple bond–containing compounds is intimately related to the catalysis and is discussed in section 7. Finally, section 8 compiles miscellaneous topics, including annulations of the Hüisgen zwitterion, phosphine-mediated reductions, iminophosphorane organocatalysis, and catalytic variants of classical phosphine oxide–generating reactions.

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Section: Phosphine Catalysis Of Allenes With Electrophilesmentioning

confidence: 99%

Phosphine Organocatalysis

et al. 2018

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“…Considerable research efforts have been devoted to the development of new methods for the phosphine-catalyzed enantioselective reactions. The use of phosphine catalysts has introduced a set of elementary steps that operate via discrete reactive species, allowing access to natural products and pharmaceuticals (Tran and Kwon, 2005;Andrews and Kwon, 2012;Han et al, 2012;Wang and Krische, 2003;Cai et al, 2016). One particularly versatile and reactive species is the phosphine-mediated 1,4-dipole generated upon addition of the phosphine catalyst to an allenoate substrate, thus providing a concise approach for accessing enantioselective annulations.…”

Section: Introductionmentioning

confidence: 99%

Enantioselective [4+2] Annulation to the Concise Synthesis of Chiral Dihydrocarbazoles

Wang

et al. 2020

iScience

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A highly efficient phosphine-catalyzed enantioselective [4 + 2] annulation of allenoates with 3-nitroindoles or 3-nitrobenzothiophenes has been developed. The protocol represents a unique dearomatizationaromatization process to access functionalized dihydrocarbazoles or dihydrodibenzothiophenes with high optical purity (up to 97% ee) under mild reaction conditions. The synthetic utility of the highly enantioselective [4 + 2] annulation enables a concise synthesis of analgesic agent.

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“…Krische and coworkers documented the first intramolecular [3 + 2] annulation of electron-deficient 1,7-enynes 111 for diastereoselective synthesis of diquinanes 112 (eq a). 85 The same group subsequently developed a concise total synthesis of c). 87 To date, there are only two reports on phosphine-catalyzed enantioselective intramolecular [3 + 2] annulations, unlike multitudinous known intermolecular variants.…”

Section: Scheme 2 Main Reaction Modes Of Allenes In Phosphine Catalysismentioning

confidence: 99%

Phosphine-Catalyzed Asymmetric Organic Reactions

2018

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Asymmetric phosphine catalysis showcasing remarkable progress over the past two decades has emerged as a key synthetic platform for the creation of molecular frameworks encountered in medicinal chemistry and materials science. Different types of novel chiral phosphine catalysts have been developed and employed in cornucopias of organic transformations, such as annulation, addition, Morita-Baylis-Hillman, and Rauhut-Currier reactions, among others. This review summarizes all of the literature examples from late 1990s to the end of 2017, alongside their mechanistic insights whenever possible, with a very aim to trigger more intensive research in the future to render asymmetric phosphine catalysis one of the most common and reliable tools to organic chemists.

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Catalytic Diastereoselective Synthesis of Diquinanes from Acyclic Precursors.

Cited by 104 publications

References 2 publications

Phosphine Organocatalysis

Phosphine Organocatalysis

Enantioselective [4+2] Annulation to the Concise Synthesis of Chiral Dihydrocarbazoles

Phosphine-Catalyzed Asymmetric Organic Reactions

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