A New Short Synthesis of (±)-Olean through Cross Metathesis

A set of experiments in surface-initiated ring-opening metathesis polymerization, including end-functionalization of growing brushes and contact angle/cyclic voltammetry measurements. We report preparation and CV of two different conjugated polymer films, and several endgroup and sidechain functionalization experiments using cross-metathesis and active ester substitution.<br>

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Synthesis of Conjugated Triynes via Alkyne Metathesis

10.26434/chemrxiv.8342534.v2 ◽

2019 ◽

Author(s):

Idriss Curbet ◽

Sophie Colombel-Rouen ◽

Romane Manguin ◽

Anthony Clermont ◽

Alexandre Quelhas ◽

...

Keyword(s):

Steric Hindrance ◽

High Selectivity ◽

Alkyne Metathesis ◽

Cross Metathesis ◽

Synthetic Strategy ◽

Sterically Hindered ◽

Site Selective

<div> <div> <div> <div> <p>The synthesis of conjugated triynes by molybdenum-catalyzed alkyne metathesis is reported. Strategic to the success of this approach is the utilization of sterically-hindered diynes that allowed for the site- selective alkyne metathesis to produce the desired con- jugated triyne products. The steric hindrance of alkyne moiety was found to be crucial in preventing the for- mation of diyne byproducts. This novel synthetic strategy was amenable to self- and cross-metathesis providing straightforward access to the corresponding symmetrical and dissymmetrical triynes with high selectivity. </p> </div> </div> </div> </div>

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A Short Synthesis of (+)-Brefeldin C via Enantioselective Radical Hydroalkynylation

10.26434/chemrxiv.8397731.v1 ◽

2019 ◽

Author(s):

Lars Gnägi ◽

Severin Vital Martz ◽

Daniel Meyer ◽

Robin Marc Schärer ◽

Philippe Renaud

Keyword(s):

Total Synthesis ◽

Natural Product ◽

Oxidation State ◽

Single Step ◽

Radical Process ◽

Target Molecule ◽

Short Synthesis ◽

The One

<div><div><div><div><p>A very concise total synthesis of (+)-brefeldin C starting from 2-furanylcyclopentene is described. This approach is based on an unprecedented enantioselective radical hydroalkynylation process to introduce the two cyclopentane stereocenters in a single step. The use of a furan substituent allows to achieve a high trans diastereoselectivity during the radical process and it contains the four carbon atoms C1–C4 of the natural product in an oxidation state closely related to the one of the target molecule. The eight-step synthesis require six product purifications and it provides (+)-brefeldin C in 18% overall yield.</p></div></div></div></div>

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A Short Synthesis of the Plant Alkaloid 4-Methyl-2,6-naphthyridine

Letters in Organic Chemistry ◽

10.2174/1570178616666181116110647 ◽

2019 ◽

Vol 16 (12) ◽

pp. 931-934 ◽

Cited By ~ 2

Author(s):

Alexandra Kamlah ◽

Franz Bracher

Keyword(s):

Pyridine Ring ◽

Cross Coupling ◽

Antirrhinum Majus ◽

New Synthesis ◽

Short Synthesis ◽

Regioselective Oxidation ◽

Key Steps

: A new synthesis of the 2,6-naphthyridine alkaloid 4-methyl-2,6-naphthyridine from Antirrhinum majus has been developed. Key steps are a regioselective oxidation of 3-bromo-4,5- dimethylpyridine to the corresponding 4-formyl derivative, and the annulation of the second pyridine ring by Suzuki-Miyaura cross-coupling using (E)-2-ethoxyvinylboronic acid pinacol ester as a masked acetaldehyde equivalent. This protocol gives the alkaloid in four steps starting from commercially available 3,4-dimethylpyridine in 15% overall yield. This annulation protocol should be useful for the synthesis of other condensed pyridines as well.

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Concise Total Synthesis of Curvulone B

Synlett ◽

10.1055/a-1297-6838 ◽

2020 ◽

Author(s):

Debendra K. Mohapatra ◽

Shivalal Banoth ◽

Utkal Mani Choudhury ◽

Kanakaraju Marumudi ◽

Ajit C. Kunwar

Keyword(s):

Total Synthesis ◽

Stereoselective Synthesis ◽

Ring System ◽

Bond Forming ◽

Cross Metathesis ◽

Bond Forming Reactions ◽

Key Steps

AbstractA concise and convergent stereoselective synthesis of curvulone B is described. The synthesis utilized a tandem isomerization followed by C–O and C–C bond-forming reactions following Mukaiyama-type aldol conditions for the construction of the trans-2,6-disubstituted dihydropyran ring system as the key steps. Other important features of this synthesis are a cross-metathesis, epimerization, and Friedel–Crafts acylation.

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