Total Synthesis of (−)-Actinophyllic Acid Enabled by a Key Dual Ir/Amine-Catalyzed Allylation

Organic Letters, Год журнала: 2018, Номер 20(15), С. 4575 - 4578

Опубликована: Июль 13, 2018

A synthetic strategy for the catalytic asymmetric total synthesis of (−)-actinophyllic acid is described. This highly efficient and enantioselective approach allows rapid installation four contiguous chiral centers (C16, C15, C20, C19) by way a dual Ir/amine allylation 2-indolyl vinyl carbinol 6 an aldol reaction resultant aldehyde 4a with 2-pyrrolidinone 5. The key indol-3-ylmethanamine moiety 1-azabicyclo[4.2.1]nonane ring system were readily generated through selective Mannich-like cyclization intramolecular N-alkylation, respectively.

Язык: Английский

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Enantioselective Ir-Catalyzed Allylic Alkylation of Racemic Allylic Alcohols with Malonates

Organic Letters, Год журнала: 2019, Номер 21(3), С. 840 - 843

Опубликована: Янв. 23, 2019

Ir-catalyzed enantioselective allylic alkylation of branched racemic alcohols with malonates is described. Enabled by Carreira's chiral Ir/(P, olefin) complex, the method described allows substitution various aromatic and excellent enantioselectivity. The could be used directly as efficient nucleophiles without need preactivation.

Язык: Английский

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Bioinspired Divergent Oxidative Cyclizations of Geissoschizine: Total Synthesis of (–)‐17‐nor‐Excelsinidine, (+)‐16‐epi‐Pleiocarpamine, (+)‐16‐Hydroxymethyl‐Pleiocarpamine and (+)‐Taberdivarine H

European Journal of Organic Chemistry, Год журнала: 2020, Номер 2020(40), С. 6340 - 6351

Опубликована: Сен. 2, 2020

We report a full account of our efforts towards bioinspired oxidative cyclizations geissochizine and analogs to mimic the biosynthesis mavacuran, akuammilan , excelsinidine groups monoterpene indole alkaloids. The construction A,B,C,D ring system geissoschizine was first achieved by merging two known syntheses this alkaloid. Modified Ma's conditions (KHMDS/I 2 ) applied directly induced formation N4–C16 bond encountered in excelsinidines core. Identical C16‐dimethylmalonate‐containing N4‐quaternized substrates ended mavacurans core (N1–C16 bond). With unified cyclization strategy: (–)‐17‐ nor ‐excelsinidine, (+)‐16‐ epi ‐pleiocarpamine, (+)‐16‐hydroxymethyl‐pleiocarpamine, 16‐formyl‐pleiocarpamine (+)‐taberdivarine H were synthetized. also shortened total synthesis 16‐ ‐pleiocarpamine compared preliminary communication from C16‐monoester analog. Alternatively, 17‐ ‐excelsinidine synthesized via an intramolecular nucleophilic substitution 7‐membered α‐chlorolactam prepared 16‐desformyl‐geissoschizine.

Язык: Английский

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Bioinspired Oxidative Cyclization of the Geissoschizine Skeleton for the Total Synthesis of (−)‐17‐nor‐Excelsinidine

Angewandte Chemie, Год журнала: 2018, Номер 130(38), С. 12474 - 12478

Опубликована: Март 25, 2018

Abstract We report the first total synthesis of (−)‐17‐nor‐excelsinidine, a zwitterionic monoterpene indole alkaloid that displays an unusual N4−C16 connection. Inspired by postulated biosynthesis, we explored oxidative coupling approach from geissoschizine framework to forge key ammonium–acetate Two strategies allowed us achieve this goal, namely intramolecular nucleophilic substitution on 16‐chlorolactam with N4 nitrogen atom or direct I 2 ‐mediated enolate geissoschizine.

Язык: Английский

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Brønsted-Acid-Catalyzed Synthesis of 3-Alkoxy and 3-Sulfamido Indanones via a Tandem Cyclization

The Journal of Organic Chemistry, Год журнала: 2019, Номер 84(13), С. 8497 - 8508

Опубликована: Май 22, 2019

Brønsted-acid-catalyzed allylic substitution reactions of the in situ generated 3-hydroxy indanones with alcohols and sulfamides were investigated, which provided a facile route for synthesis large variety 3-alkoxy 3-sulfamido indanones. The key intermediates, indanones, obtained through intramolecular Meyer-Schuster rearrangement o-propargyl alcohol benzaldehydes. resulting 3-benzyloxy indanone could be selectively modified by sulfonamidation reduction reactions.

Язык: Английский

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Trimethyl Orthoacetate and Ethylene Glycol Mono‐Vinyl Ether as Enolate Surrogates in Enantioselective Iridium‐Catalyzed Allylation

Angewandte Chemie, Год журнала: 2018, Номер 130(26), С. 7780 - 7784

Опубликована: Май 2, 2018

Abstract Trimethyl orthoacetate and ethylene glycol mono‐vinyl ether are employed in iridium‐catalyzed enantioselective allylation reactions. The method documented enables their convenient use as surrogates for silyl ketene acetals enol ethers to prepare γ,δ‐unsaturated esters protected aldehydes with excellent enantioselectivity. utility of this novel has been demonstrated by its implementation a formal synthesis the meroterpenoid (+)‐conicol.

Язык: Английский

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Recent advances in cyclization reactions via catalytic allylic substitution for the asymmetric synthesis of heterocyclic compounds

Tetrahedron Letters, Год журнала: 2024, Номер 141, С. 155071 - 155071

Опубликована: Апрель 17, 2024

Язык: Английский

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Iridium-Catalyzed Enantioselective Allylation of Aryl Enamides and Enecarbamates

Organic Letters, Год журнала: 2019, Номер 21(7), С. 2449 - 2452

Опубликована: Март 21, 2019

Aromatic enamide and enecarbamate as a novel type of nucleophile in the asymmetric allylation branched, racemic allylic alcohols to give homoallylic ketones has been described. Enabled by Carreira's chiral Ir (P, olefin) complex, reactions proceed good yields with excellent enantioselectivities.

Язык: Английский

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Enantioselective Construction of Pyrimidine‐Fused Diazepinone Derivatives Bearing a Tertiary Stereogenic Center Enabled by Iridium‐Catalysed Intramolecular Allylic Substitution

Advanced Synthesis & Catalysis, Год журнала: 2021, Номер 363(13), С. 3227 - 3232

Опубликована: Май 22, 2021

Abstract The iridium‐catalysed enantioselective intramolecular allylic substitution of pyrimidine‐tethered carbonates was developed. A wide range chiral pyrimidine‐fused diazepinone derivatives were successfully constructed in 88–96% yields with 85–99% ees. This work further highlights the power chiral‐bridged biphenyl phosphoramidites asymmetric synthesis. magnified image

Язык: Английский

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Palladium catalyzed reductive Heck coupling and its application in total synthesis of (−)-17-nor-excelsinidine

RSC Advances, Год журнала: 2021, Номер 11(13), С. 7570 - 7574

Опубликована: Янв. 1, 2021

17-nor-Excelsinidine was constructed via oxidative coupling in excellent yield and high regioselectivity under NBS/pyridine from the enolate of geissoschizine.

Язык: Английский

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