Phosphine-catalyzed synthesis of β-lactones from ketenes and chiral β-oxyaldehydes

Chen, Shi; Mondal, Mukulesh; Adams, Matthew P.; Wheeler, Kraig A.

doi:10.1016/j.tetlet.2015.09.141

Cited by 5 publications

(3 citation statements)

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“…We had previously had success in developing a disubstituted ketene (ketoketene) homodimerization reaction and related reactions through the use of phosphine catalysis. 11 However, phosphine catalysts (Binaphane, Josiphos, and PBu 3 ) were found to be too active to facilitate the desired heterodimerization, leading generally to oligomerization of the donor ketene, or suffering from catalyst deactivation under in situ ketene generation conditions. Inspired by Calter's work on the alkaloid-catalyzed ketene homodimerization reaction, we proceeded to evaluate cinchona alkaloid derivatives as promoters of the ketene heterodimerization reaction.…”

Section: Resultsmentioning

confidence: 99%

“…This involved examining the reaction of methylphenylketene, which would act as the less reactive ketene ( acceptor ketene ), with methylketene (generated in situ from propionyl chloride), which would act as the more reactive ketene ( donor ketene ). We had previously had success in developing a disubstituted ketene (ketoketene) homodimerization reaction and related reactions through the use of phosphine catalysis . However, phosphine catalysts (Binaphane, Josiphos, and PBu 3 ) were found to be too active to facilitate the desired heterodimerization, leading generally to oligomerization of the donor ketene or suffering from catalyst deactivation under in situ ketene generation conditions.…”

Section: Resultsmentioning

confidence: 99%

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Catalytic Asymmetric Synthesis of Ketene Heterodimer β-Lactones: Scope and Limitations

et al. 2016

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In this article we describe extensive studies of the catalytic asymmetric heterodimerization of ketenes to give ketene heterodimer β-lactones. The optimal catalytic system was determined to be a cinchona alkaloid derivative (TMS-quinine or Me-quinidine). The desired ketene heterodimer β-lactones were obtained in good to excellent yields (up to 90%), with excellent levels of enantioselectivity (≥90% ee for 33 Z- and E-isomer examples), good to excellent Z-olefin isomer selectivity (≥90:10 for 20 examples), and with excellent regioselectivity (only one regioisomer formed). Full details of catalyst development studies, catalyst loading investigations, substrate scope exploration, protocol innovations (including double in situ ketene generation for 7 examples), and an application to a cinnabaramide A intermediate are described. The addition of lithium perchlorate (1-2 equiv) as an additive to the alkaloid catalyst system was found to favor formation of the E-isomer of the ketene heterodimer. 10 examples were formed with moderate to excellent E-olefin isomer selectivity (74:25 to 97:3) and with excellent enantioselectivity (84-98% ee).

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Catalytic Asymmetric Synthesis of Ketene Heterodimer β-Lactones: Scope and Limitations

et al. 2016

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“…The Kerrigan group also reported the trialkylphosphine-catalyzed [2 + 2] cycloadditions of disubstituted ketenes and chiral β -oxyaldehydes, affording β -lactones bearing up to three stereogenic centers in moderate to excellent yields and with moderate to good diastereoselectivities (Scheme 640). 708 From a test of several nucleophilic phosphines, including ( R )-Binaphane, ( R )-Binepine, dppb, P( c -hexyl) 3 , PMe 3 , and PBu 3 , the latter was the optimal catalyst for the reactions performed in dichloromethane or THF at −78 °C.…”

Section: Miscellaneous Phosphine Catalysismentioning

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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Organophosphines‐Catalyzed Cycloaddition Reactions

Wei

Shi

2018

Organocatalytic Cycloadditions for Synthesis of Carbo‐ and Heterocycles

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Phosphine-catalyzed synthesis of β-lactones from ketenes and chiral β-oxyaldehydes

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Cited by 5 publications

References 34 publications

Catalytic Asymmetric Synthesis of Ketene Heterodimer β-Lactones: Scope and Limitations

Catalytic Asymmetric Synthesis of Ketene Heterodimer β-Lactones: Scope and Limitations

Phosphine Organocatalysis

Organophosphines‐Catalyzed Cycloaddition Reactions

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