An enantioselective synthesis of (+)-hygroline and (+)-pseudohygroline via Keck allylation and CBS reduction

Bhoite, Shubhangi P.; Kamble, Rohit B.; Suryavanshi, Gurunath

doi:10.1016/j.tetlet.2015.06.012

Cited by 12 publications

(8 citation statements)

References 35 publications

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“…Finally, we used our benchmark catalysts for the substitution on piperidine 1 e with isopropenyloxy‐trimethylsilane 2 n and obtained the corresponding ( S )‐(−)‐pelletierine precursor 3 t with IDPi 7 d in 46 % isolated yield with an enantiomeric ratio of 86.5 : 13.5. It is noteworthy that product 3 a and its derivatives access a palette of different pyrrolidine and sedum alkaloids in only a few literature known steps [56–59] . In total we accessed the precursors for ( S )‐(+)‐homoproline and six pyrrolidine and sedum alkaloids with high yields and enantioselectivities.…”

Section: Figurementioning

confidence: 99%

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Catalytic Asymmetric Additions of Enol Silanes to In Situ Generated Cyclic, AliphaticN‐Acyliminium Ions

et al. 2022

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Strong and confined imidodiphosphorimidate (IDPi) catalysts enable highly enantioselective substitutions of cyclic, aliphatic hemiaminal ethers with enol silanes. 2-Substituted pyrrolidines, piperidines, and azepanes are obtained with high enantioselectivities, and the method displays a broad tolerance of various enol silane nucleophiles. Several natural products can be accessed using this methodology. Mechanistic studies support the intermediacy of non-stabilized, cyclic N-(exo-acyl)iminium ions, paired with the confined chiral counteranion. Computational studies suggest transition states that explain the observed enantioselectivity.

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Section: Figurementioning

confidence: 99%

“…It is noteworthy that product 3 a and its derivatives access a palette of different pyrrolidine and sedum alkaloids in only a few literature known steps. [56][57][58][59] In total we accessed the precursors for (S)-(+)-homoproline and six pyrrolidine and sedum alkaloids with high yields and enantioselectivities.…”

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confidence: 99%

Catalytic Asymmetric Additions of Enol Silanes to In Situ Generated Cyclic, AliphaticN‐Acyliminium Ions

et al. 2022

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“…Treatment of butyl glycol 20 with BnBr/NaH/TBAI in DMF-THF gave the mono- O -benzylated alcohol 21 in 91% yield. Swern oxidation of alcohol 21 afforded aldehyde 16 (89%), which on enantioselective Keck allylation using ( S )-BINOL produced alcohol 15 (93% ee) [59]. Using ( R )-BINOL as the ligand, alcohol ent -15 was also prepared by the same method (See the Supplementary Materials for HPLC analysis of compounds 15 and ent -15 ).…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Glycosidase Inhibition of Broussonetine M and Its Analogues

Kinami

Kato

et al. 2019

Molecules

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Cross-metathesis (CM) and Keck asymmetric allylation, which allows access to defined stereochemistry of a remote side chain hydroxyl group, are the key steps in a versatile synthesis of broussonetine M (3) from the d-arabinose-derived cyclic nitrone 14. By a similar strategy, ent-broussonetine M (ent-3) and six other stereoisomers have been synthesized, respectively, starting from l-arabino-nitrone (ent-14), l-lyxo-nitrone (ent-3-epi-14), and l-xylo-nitrone (2-epi-14) in five steps, in 26%–31% overall yield. The natural product broussonetine M (3) and 10’-epi-3 were potent inhibitors of β-glucosidase (IC50 = 6.3 μM and 0.8 μM, respectively) and β-galactosidase (IC50 = 2.3 μM and 0.2 μM, respectively); while their enantiomers, ent-3 and ent-10’-epi-3, were selective and potent inhibitors of rice α-glucosidase (IC50 = 1.2 μM and 1.3 μM, respectively) and rat intestinal maltase (IC50 = 0.29 μM and 18 μM, respectively). Both the configuration of the polyhydroxylated pyrrolidine ring and C-10’ hydroxyl on the alkyl side chain affect the specificity and potency of glycosidase inhibition.

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“…[36,37] Im Gegensatz dazu führten Imidodiphosphat das Produkt 3 a und seine Derivate in nur wenigen literaturbekannten Schritten Zugang zu einer Palette verschiedener Pyrrolidin-und Sedumalkaloide ermöglichen. [56][57][58][59] Insgesamt haben wir die Vorstufen für (S)-(+)-Homoprolin und sechs Pyrrolidin-und Sedumalkaloide mit hohen Ausbeuten und Enantioselektivitäten zugänglich gemacht.…”

Section: Seit Frühen Berichten In Den 1950er Jahren Werden N-unclassified

Katalytische asymmetrische Additionen von Enolsilanen an in situ erzeugte zyklische, aliphatischeN‐Acyliminiumionen

et al. 2022

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Starke und sterisch umzäunte Imidodiphosphorimidatkatalysatoren (IDPi) ermöglichen hochenantioselektive Substitutionen von zyklischen, aliphatischen Hemiaminalethern mit Enolsilanen. 2‐Substituierte Pyrrolidine, Piperidine und Azepane werden mit hoher Enantioselektivität erhalten, und die Methode zeigt eine breite Toleranz gegenüber verschiedenen Enolsilanen. Mehrere Naturstoffe lassen sich mit dieser Methode gewinnen. Mechanistische Studien bestärken die Bildung des Ionenpaares zwischen nicht‐stabilisierten, zyklischen N‐(exo‐Acyl)iminiumionen, und dem sterisch umzäunten chiralen Gegenanion. Theoretische Studien legen Übergangszustände nahe, welche die beobachtete Enantioselektivität erklären.

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An enantioselective synthesis of (+)-hygroline and (+)-pseudohygroline via Keck allylation and CBS reduction

Cited by 12 publications

References 35 publications

Catalytic Asymmetric Additions of Enol Silanes to In Situ Generated Cyclic, AliphaticN‐Acyliminium Ions

Catalytic Asymmetric Additions of Enol Silanes to In Situ Generated Cyclic, AliphaticN‐Acyliminium Ions

Synthesis and Glycosidase Inhibition of Broussonetine M and Its Analogues

Katalytische asymmetrische Additionen von Enolsilanen an in situ erzeugte zyklische, aliphatischeN‐Acyliminiumionen

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