Merging singlet-oxygen induced furan oxidations with organocatalysis: synthesis of enantiopure cyclopentanones and hydrindanes

Kalaitzakis, Dimitris; Sofiadis, Manolis; Tsopanakis, Vasileios; Montagnon, Tamsyn; Vassilikogiannakis, Georgios

doi:10.1039/d0ob00468e

“…2). Furthermore, our group [13] and Vassilikogiannakis' group [14] reported the synthesis of chiral hydrindanes using diphenylprolinol silyl ether medi-Scheme 1. Michael reaction and domino reactions using diphenylprolinol silyl ether.…”

Section: Introductionmentioning

confidence: 99%

Asymmetric Synthesis of Corey Lactone and Latanoprost

Umekubo

¹

,

Hayashi

²

2020

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Corey lactone was synthesized in a single pot within 152 minutes in a 50 % overall yield via pot and time economical manner. Latanoprost, an antiglaucoma blockbuster drug, was also synthesized via seven pot reaction with five purifications in a 25 % total yield. One of the key reactions is asymmetric domino Michael/Michael reaction, formal [3+2] cycloaddition reaction, of 3‐(dimethylphenylsilyl)propenal and ethyl 4‐oxo‐2‐pentenoate, catalyzed by diphenylprolinol silyl ether, which constructed the core substituted cyclopentanone derivative with nearly optically pure form.

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“…The non‐productive energy and electron transfer between photocatalysts (inter‐catalyst quenching) is thought to present an insurmountable hurdle to the use of multiple catalysts within the same cascade sequence. Dual catalysis, including one photocatalytic step, has been recorded; [12a, 13, 14] however, the second catalytic entity brings something else to the transformation (such as, use of an organocatalyst to induce enantioselectivity alongside the photochemical process [13, 14] ). In the investigations described herein, we provide two solutions to this conundrum.…”

Section: Introductionmentioning

confidence: 99%

Multi‐Photocatalyst Cascades: Merging Singlet Oxygen Photooxygenations with Photoredox Catalysis for the Synthesis of Alkaloid Frameworks

Kalaitzakis

¹

,

Bosveli

²

,

Sfakianaki

³

et al. 2020

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The development of photocascades that rapidly transform simple and readily accessible furan substrates into polycyclic alkaloid frameworks or erythrina natural products is described. Each of the sequences developed makes use of photocatalyzed energy transfer processes, which generate singlet oxygen, to set up the substrates for the second photocatalyzed reaction, wherein electron transfer generates carbon‐centered radicals for the cyclizations that give the final complex frameworks. A chemical switch has been developed that can “switch off” one photocatalyst; thus, allowing a second photocatalyst to take over control of the sequence. As a corollary, this strategy represents the first time it has been possible to use multiple photocatalysts in photocascades, and, as such, it expands significantly the reactions that can be included in such cascades and the order in which they can be initiated.

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“…There are examples of multiple oxidative or reductive quenches,o r, more,r arely mixed redox or energy/ electron transfer steps;b ut, as ingle photocatalyst is always employed. [12] Then on-productive energy and electron transfer between photocatalysts (inter-catalyst quenching) is thought to present an insurmountable hurdle to the use of multiple catalysts within the same cascade sequence.D ual catalysis,i ncluding one photocatalytic step,h as been recorded; [12a, 13, 14] however,t he second catalytic entity brings something else to the transformation (such as,u se of an organocatalyst to induce enantioselectivity alongside the photochemical process [13,14] ). In the investigations described herein, we provide two solutions to this conundrum.…”

Section: Introductionmentioning

confidence: 99%

Multi‐Photocatalyst Cascades: Merging Singlet Oxygen Photooxygenations with Photoredox Catalysis for the Synthesis of Alkaloid Frameworks

Kalaitzakis

¹

,

Bosveli

²

,

Sfakianaki

³

et al. 2020

Self Cite

View full text Add to dashboard Cite

The development of photocascades that rapidly transform simple and readily accessible furan substrates into polycyclic alkaloid frameworks or erythrina natural products is described. Each of the sequences developed makes use of photocatalyzed energy transfer processes, which generate singlet oxygen, to set up the substrates for the second photocatalyzed reaction, wherein electron transfer generates carbon‐centered radicals for the cyclizations that give the final complex frameworks. A chemical switch has been developed that can “switch off” one photocatalyst; thus, allowing a second photocatalyst to take over control of the sequence. As a corollary, this strategy represents the first time it has been possible to use multiple photocatalysts in photocascades, and, as such, it expands significantly the reactions that can be included in such cascades and the order in which they can be initiated.

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Merging singlet-oxygen induced furan oxidations with organocatalysis: synthesis of enantiopure cyclopentanones and hydrindanes

Abstract: A general, flexible and highly effective method for the regio-, diastereo- & enantioselective one-pot synthesis of important carbocycles, namely, enantiopure cyclopentanones and their hydrindane congeners is presented.

Cited by 19 publications

References 91 publications

Asymmetric Synthesis of Corey Lactone and Latanoprost

Asymmetric Synthesis of Corey Lactone and Latanoprost

Multi‐Photocatalyst Cascades: Merging Singlet Oxygen Photooxygenations with Photoredox Catalysis for the Synthesis of Alkaloid Frameworks

Multi‐Photocatalyst Cascades: Merging Singlet Oxygen Photooxygenations with Photoredox Catalysis for the Synthesis of Alkaloid Frameworks

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