Stereoselective synthesis of (.+-.)-1-0-methylloganin, 10-hydroxyloganin, secologanin, and sweroside aglucons from a common 1-hydroxy-4a,5,8,8a-tetrahydroisochromene synthon

Nakane, Masami; Hutchinson, C. Richard

doi:10.1021/jo01309a037

Cited by 16 publications

(3 citation statements)

References 3 publications

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“…This known step would build the tetrahydro-β-carboline ring, establish the stereochemistry at the C3 stereocenter, and provide a platform for the synthesis of unnatural strictosidine analogs. It should be emphasized that secologanin derivatives have been popular synthetic targets, yet only one synthesis of this compound exists, as reported by Ishikawa in 2019. − (−)-Secologanin ( 6 ) could be obtained from vinylogous ester 7 through a series of manipulations, including introduction of the terminal olefin and oxidative cleavage of the five-membered ring. In a key step, the dihydropyran of vinylogous ester 7 could be accessed by an inverse electron-demand hetero-Diels–Alder reaction between enal 8 and enol ether 9 .…”

Section: Resultsmentioning

confidence: 99%

Total Synthesis of (−)-Strictosidine and Interception of Aryne Natural Product Derivatives “Strictosidyne” and “Strictosamidyne”

et al. 2021

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Monoterpene indole alkaloids are a large class of natural products derived from a single biosynthetic precursor, strictosidine. We describe a synthetic approach to strictosidine that relies on a key facially selective Diels–Alder reaction between a glucosyl-modified alkene and an enal to set the C15–C20–C21 stereotriad. DFT calculations were used to examine the origin of stereoselectivity in this key step, wherein two of 16 possible isomers are predominantly formed. These calculations suggest the presence of a glucosyl unit, also inherent in the strictosidine structure, guides diastereoselectivity, with the reactive conformation of the vinyl glycoside dienophile being controlled by an exo-anomeric effect. (−)-Strictosidine was subsequently accessed using late-stage synthetic manipulations and an enzymatic Pictet–Spengler reaction. Several new natural product analogs were also accessed, including precursors to two unusual aryne natural product derivatives termed “strictosidyne” and “strictosamidyne”. These studies provide a strategy for accessing glycosylic natural products and a new platform to access monoterpene indole alkaloids and their derivatives.

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Section: Resultsmentioning

confidence: 99%

Total Synthesis of (−)-Strictosidine and Interception of Aryne Natural Product Derivatives “Strictosidyne” and “Strictosamidyne”

et al. 2021

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“…[13,14] Indeed, the latter would arise from the Pictet-Spengler reaction [15] of as ecologanin derivative 8 which would be obtained as described by Tietze three decades ago. [16][17][18] It involved ad omino sequence of aK noevenagel condensation between monoprotected malondialdehyde 9 and 3-formyl-1,1,1-trichloroacetone 10 followed by an inverse-demand hetero Diels-Alder cycloaddition between generated enal 11 and enol ether 12. [16a] Methanolysis, sulfoxide elimination, and release of the aldehyde from the dithiane furnished secologanin aglycon 8.…”

Section: Angewandte Chemiementioning

confidence: 99%

Enantioselective Total Synthesis of Cymoside through a Bioinspired Oxidative Cyclization of a Strictosidine Derivative

et al. 2019

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The first total synthesis of the caged monoterpene indole alkaloid cymoside is reported. This natural product displays aunique hexacyclic-fused skeleton whose biosynthesis implies an early oxidative cyclization of strictosidine.O ur approach to the furo[3,2-b]indoline framework relied on an unprecedented biomimetic sequence whichs tarted by the diastereoselective oxidation of the indole ring into ah ydroxyindolenine which triggered the addition of an enol ether and was followed by the trapping of an oxocarbenium intermediate.

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“…Indeed, the syntheses of simple secoiridoids such as oleocanthal have been accomplished by Smith, Williams, and Vidari. , Several synthetic and hemisynthetic strategies have also been deployed to access the aglycone of secologanin by Tietze, , Hutchinson and Partridge, Isoe, Chang, and Tai . In 2019, Ishikawa achieved the first enantioselective total synthesis of secologanin itself via the key organocatalyzed anti -1,4-addition of an aldehyde onto a Michael acceptor .…”

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confidence: 99%

Synthesis of a Seco iso-Secologanin Aglycone Analogue of Interest toward Secoiridoids and Monoterpene Indole Alkaloids

et al. 2021

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We report the access to an acyclic iso-secologanin aglycone analogue relevant to seco-iridois and monoterpene indole alkaloids. Its synthesis involved a regioselective allylic alkylation of a linear dienyl carbonate with dimethyl malonate catalyzed by an iridium complex and an anti-Markovnikov Wacker-type oxidation of the terminal alkene of the branched product obtained. The aldehyde thus formed was engaged in a Pictet-Spengler reaction with tryptamine towards monoterpene indole alkaloids.

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Stereoselective synthesis of (.+-.)-1-0-methylloganin, 10-hydroxyloganin, secologanin, and sweroside aglucons from a common 1-hydroxy-4a,5,8,8a-tetrahydroisochromene synthon

Abstract: Aus dem Isochromen‐Synthon (I) erhält man über das Diol (II) den Dialdehyd (III), der mit (IV) im Gleichgewicht steht und bei der Aldolisierung die Reaktionsprodukte (V)‐(VIII) je nach den angewandten Bedingungen in recht unterschiedlichen Anteilen liefert.

Cited by 16 publications

References 3 publications

Total Synthesis of (−)-Strictosidine and Interception of Aryne Natural Product Derivatives “Strictosidyne” and “Strictosamidyne”

Total Synthesis of (−)-Strictosidine and Interception of Aryne Natural Product Derivatives “Strictosidyne” and “Strictosamidyne”

Enantioselective Total Synthesis of Cymoside through a Bioinspired Oxidative Cyclization of a Strictosidine Derivative

Synthesis of a Seco iso-Secologanin Aglycone Analogue of Interest toward Secoiridoids and Monoterpene Indole Alkaloids

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