A Step‐Economic Synthesis of (<i>S</i>)‐(−)‐Juglomycin C and (<i>S</i>)‐(−)‐NHAB by Dötz Benzannulation and Convergent Deprotections

Bhowmik, Amit; Mulay, Sandip V.; Fernandes, Rodney A.

doi:10.1002/ajoc.201900211

Cited by 8 publications

(8 citation statements)

References 29 publications

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“…FLPs, which are systems made of a Lewis base prevented to react with an acidic Lewis counterpart, are of great interest since they can activate small molecules like H 2 or CO 2 , and lead to new and original reactive systems for catalysis . We turned our attention to the Morita–Baylis–Hillman (MBH) reaction since the α‐methylene‐β‐hydroxy‐carbonyl derivatives obtained by this atom‐economical reaction are key intermediates and valuable building blocks in the synthesis of complex natural products and bio‐active compounds . This reaction is usually catalyzed in the presence of a nucleophilic base, such as amines, or phosphines, that can be combined with a transition‐metal complex to increase the reaction rate .…”

Section: Figuresupporting

confidence: 71%

Endohedral Functionalized Cage as a Tool to Create Frustrated Lewis Pairs

et al. 2018

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A frustrated Lewis pair (FLP) system was obtained by confinement of the Lewis base partner, a Verkade's superbase, in a molecular cavity. Whereas the model superbase lacking cavity displayed no catalytic activity in Morita-Baylis-Hillman (MBH) reactions, when associated to titanium (IV) chloride, the encaged superbase turns out to be an efficient catalyst under the same conditions. The crucial role of the endohedral functionalized cage on catalytic performance was further demonstrated by the fact that model superbases with bulky substituents were much less efficient to produce active catalysts, as well as by inhibition and substrate selection experiments. P NMR spectroscopy and mass spectrometry experiments evidenced that no interaction between the Lewis acidic and basic partners occurred when the superbase was capped by a cycloveratrylene (CTV) unit, thus creating a true FLP active system.

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Section: Figuresupporting

confidence: 71%

Endohedral Functionalized Cage as a Tool to Create Frustrated Lewis Pairs

et al. 2018

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“…Later, the naphthalene derivative 56 was subjected to CAN‐oxidation to deliver the quinone 57 which on subsequent hydrolysis in the presence of AlCl 3 furnished the (S)‐(‐)‐juglomycin C ( 60) in good yield. On the other hand, the compound 57 was also reacted with acetic anhydride in pyridine to produce acetyl protected compound 58 which on further treatment with AlCl 3 gave the desired natural product (S)‐(‐)‐NHAB ( 59) (Scheme ) …”

Section: Synthesis Of Natural Productsmentioning

confidence: 99%

The Dötz Benzannulation Reaction: A Booming Methodology for Natural Product Synthesis

2020

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Since its finding in 1975, the Dötz benzannulation reaction has attracted a great attention of the scientific community as it permits the regio‐controlled construction of functionalised aromatic frameworks from acyclic precursors. In recent years, this beautifully simple yet much powerful technique for the formation of C−C bonds has opened‐up new possibilities in modern synthetic organic chemistry. In this Review, we report the developments in natural products synthesis by employing the Dötz benzannulation as a key transformation. Although, a flow of publications have witnessed a constant progress in this wonderful area of research, but to our best knowledge this is the first review which purely focuses on the applications of the Dötz benzannulation reaction in natural product synthesis. We are assured that this review will act as a promoter in amplifying the applications of the Dötz benzannulation in the domain of synthetic organic chemistry.

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“…Moreover, the highly substituted alkenes have been utilized as intermediates for numerous synthetic diversifications, [19] and allow construction of various structural units in the realms of heterocyclic and natural product chemistry. [20]…”

Section: Introductionmentioning

confidence: 99%

Site‐Specific S‐Allylation of α‐Enolic Dithioesters with Morita‐Baylis‐Hillman Acetates at Room Temperature: Precursor for Thiopyrans

et al. 2019

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An efficient one-pot allylic alkylation of α-enolic dithioesters (DTEs) with Morita-Baylis-Hillman (MBH) acetates has been devised in ethanol at room temperature. The reaction being site-selective provided Sallylated product exclusively with trace amount of C-allylated one. Remarkably, some of the S-allylated product undergoes [3,3]-sigmatropic rearrangement to C-allylated one under ethanol reflux. The typical feature of this protocol is the isolation of S-allylated α-oxoketene dithioacetals, a trisubstituted olefin, which have been further exploited toward the synthesis of thiopyrans. Scheme 1. Chemo-/regioselective allylation of α-enolic dithioesters with MBH acetates. Scheme 2. Transformation of compound 3 a to 5 a via [3,3] -sigmatropic rearrangement.Scheme 3. Plausible mechanism for the formation of compounds 3, 4 and 5.

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A Step‐Economic Synthesis of (S)‐(−)‐Juglomycin C and (S)‐(−)‐NHAB by Dötz Benzannulation and Convergent Deprotections

Cited by 8 publications

References 29 publications

Endohedral Functionalized Cage as a Tool to Create Frustrated Lewis Pairs

Endohedral Functionalized Cage as a Tool to Create Frustrated Lewis Pairs

The Dötz Benzannulation Reaction: A Booming Methodology for Natural Product Synthesis

Site‐Specific S‐Allylation of α‐Enolic Dithioesters with Morita‐Baylis‐Hillman Acetates at Room Temperature: Precursor for Thiopyrans

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