scholarly journals Enantioselective synthesis of polyhydroxyindolizidinone and quinolizidinone derivatives from a common precursor

2014 ◽  
Vol 10 ◽  
pp. 3104-3110 ◽  
Author(s):  
Nemai Saha ◽  
Shital K Chattopadhyay
Keyword(s):  
Enantioselective Synthesis ◽  
Synthetic Route ◽  
Common Precursor ◽  
Key Steps

A concise asymmetric synthetic route to two new tetrahydroxyindolizidinone and quinolizidinone derivatives has been developed from a common intermediate which featured a highly selective dihydroxylation reaction and a RCM reaction as key steps.

scholarly journals Studies on the Enantioselective Synthesis of E-Ethylidene-bearing Spiro[indolizidine-1,3′-oxindole] Alkaloids

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 428
Author(s):  
Nihan Yayik ◽  
Maria Pérez ◽  
Elies Molins ◽  
Joan Bosch ◽  
Mercedes Amat
Keyword(s):  
Ring System ◽  
Enantioselective Synthesis ◽  
Synthetic Route ◽  
Hydroxymethyl Group ◽  
Hydride Reduction ◽  
Lactam Carbonyl ◽  
Key Steps ◽  
Oxindole Alkaloids

A synthetic route for the enantioselective construction of the tetracyclic spiro[indolizidine-1,3′-oxindole] framework present in a large number of oxindole alkaloids, with a cis H-3/H-15 stereochemistry, a functionalized two-carbon substituent at C-15, and an E-ethylidene substituent at C-20, is reported. The key steps of the synthesis are the generation of the tetracyclic spirooxindole ring system by stereoselective spirocyclization from a tryptophanol-derived oxazolopiperidone lactam, the removal of the hydroxymethyl group, and the stereoselective introduction of the E-ethylidene substituent by acetylation at the α-position of the lactam carbonyl, followed by hydride reduction and elimination. Following this route, the 21-oxo derivative of the enantiomer of the alkaloid 7(S)-geissoschizol oxindole has been prepared.

Enantioselective Synthesis of the Sex Pheromone of Lichen Moth, Miltochrista calamine, and Its Diastereomer

Synlett ◽  
2021 ◽  
Author(s):  
Jiangchun Zhong ◽  
Gucheng Yuan ◽  
Jiawei Liu ◽  
Shihang Yu ◽  
Xueyang Wang ◽  
...  
Keyword(s):  
Sex Pheromone ◽  
Enantioselective Synthesis ◽  
Synthetic Approach ◽  
Chiral Auxiliaries ◽  
Synthetic Sex Pheromone ◽  
Key Steps

AbstractThe synthesis of a Miltochrista calamine sex pheromone and its diastereomer has been developed. The key steps of the synthetic approach involved Evans’ chiral auxiliaries and the addition of alkyne to aldehyde, which were firstly applied to prepare this sex pheromone and its diastereomer. The synthetic sex pheromone could be used to trap insects and study physiological and ecological questions of the lichen moth.

scholarly journals Total syntheses of all tri-oxygenated 16-phytoprostane classes via a common precursor constructed by oxidative cyclization and alkyl–alkyl coupling reactions as the key steps

2017 ◽  
Vol 15 (44) ◽  
pp. 9408-9414 ◽  
Author(s):  
Jakub Smrček ◽  
Radek Pohl ◽  
Ullrich Jahn
Keyword(s):  
Total Synthesis ◽  
Oxidative Cyclization ◽  
Coupling Reactions ◽  
Total Syntheses ◽  
Common Precursor ◽  
Key Steps

A parallel total synthesis of 16-F1t-, 16-E1-phytoprostanes and a first synthesis of 16-D1t-phytoprostanes based on a common precursor are described.

A Concise Enantioselective Synthesis of (S)-Preclamol via Asymmetric Catalytic Negishi Cross-Coupling Reaction

Synlett ◽  
2019 ◽  
Vol 30 (07) ◽  
pp. 860-862 ◽  
Author(s):  
Yun Zhou ◽  
Chunxiao Liu ◽  
Lifeng Wang ◽  
Leng Han ◽  
Shicong Hou ◽  
...  
Keyword(s):  
Total Yield ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Enantioselective Synthesis ◽  
Synthetic Approach ◽  
Chiral Drugs ◽  
Asymmetric Catalytic ◽  
Cross Coupling Reaction ◽  
Tertiary Carbon ◽  
Key Steps

A novel, concise, and efficient enantioselective synthesis of (S)-preclamol (87% ee, 51% total yield) has been developed. The key steps of this synthetic approach included cobalt-catalyzed asymmetric catalytic cross-coupling of α-bromo ester with arylzinc and the reduction of chiral ester to diol with a tertiary carbon atom. Moreover, it was demonstrated that our enantioselective Negishi cross-coupling was a powerful tool to construct stereogenic benzylmethyl center in chiral drugs on a gram scale.

scholarly journals An enantioselective synthesis of the C24–C40 fragment of (−)-pulvomycin

2014 ◽  
Vol 50 (38) ◽  
pp. 4901-4903 ◽  
Author(s):  
Sandra Börding ◽  
Thorsten Bach
Keyword(s):  
Synthesis Method ◽  
Cross Coupling ◽  
Enantioselective Synthesis ◽  
Pure Form ◽  
Enantiomerically Pure ◽  
Diastereoselective Addition ◽  
Key Steps

The C24–C40 fragment of (−)-pulvomycin was prepared in enantiomerically pure form using a concise synthesis method (15 linear steps from d-fucose, 6.8% overall yield) featuring a diastereoselective addition to an aldehyde, a β-selective glycosylation and a Stille cross-coupling as the key steps.

scholarly journals Total Synthesis of Ritterazine B

2021 ◽  
Author(s):  
Yasuaki Nakayama ◽  
Michael Maser ◽  
Tatsuya Okita ◽  
Anton V. Dubrovskiy ◽  
Taryn L. Campbell ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Late Stage ◽  
Unified Approach ◽  
Common Precursor ◽  
Key Steps

<a></a>The first total synthesis of the cytotoxic alkaloid ritterazine B is reported. The synthesis features a unified approach to both steroid subunits, employing a titanium-mediated propargylation reaction to achieve divergence from a common precursor. Other key steps include gold-catalyzed cycloisomerizations that install both spiroketals, and late stage C–H oxidation to incorporate the C7<a></a><a>′</a> alcohol.<br>

Enantioselective synthesis and absolute configuration determination of hydroxywilfordic acid in sesquiterpene pyridine alkaloids

2019 ◽  
Vol 17 (1) ◽  
pp. 44-48 ◽  
Author(s):  
Yue Yuan ◽  
Jong-Wha Jung ◽  
Seung-Yong Seo
Keyword(s):  
Absolute Configuration ◽  
Enantioselective Synthesis ◽  
Synthetic Route ◽  
Sesquiterpene Pyridine Alkaloids

An enantioselective synthetic route to hydroxywilfordic acid, a key subunit of sesquiterpene pyridine alkaloids such as wilfortrine, was developed.

Total Synthesis of (–)-Aristoquinoline via an Intramolecular Nitrilium Ion Cyclization

Synthesis ◽  
2021 ◽  
Author(s):  
Keith P. Reber ◽  
Priyansh D. Gujarati
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Building Block ◽  
Spectroscopic Properties ◽  
Ring System ◽  
Synthetic Route ◽  
Enantioselective Total Synthesis ◽  
Key Steps

AbstractThe enantioselective total synthesis of the alkaloid aristoquinoline has been achieved in seven steps and 26% overall yield. A new preparation of the useful synthetic building block (–)-α-terpinyl amine was also developed in order to avoid stoichiometric mercury reagents or azide-containing intermediates. Key steps in the optimized synthetic route include an intramolecular nitrilium ion cyclization to form the characteristic azabicyclo[3.3.1]nonane ring system and a dia­stereoselective reduction of the resulting imine mixture to afford the natural product. An isomer of aristoquinoline containing an exocyclic alkene was also obtained and found to exhibit unusual chromatographic and spectroscopic properties.

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