ChemInform Abstract: Synthesis of Optically Active Cyclopenta(c)pyran-4-carboxylic Acid Derivatives, Building Blocks for Iridoids. An Attractive Alternative to Asymmetric de Mayo Reaction.

ChemInform ◽  
1990 ◽  
Vol 21 (25) ◽  
Author(s):  
M. SATO ◽  
K. TAKAYAMA ◽  
K. SEKIGUCHI ◽  
Y. ABE ◽  
T. FURUYA ◽  
...  
1989 ◽  
Vol 18 (11) ◽  
pp. 1925-1928 ◽  
Author(s):  
Masayuki Sato ◽  
Kazuhisa Takayama ◽  
Keiko Sekiguchi ◽  
Yoshito Abe ◽  
Toshio Furuya ◽  
...  

2020 ◽  
Author(s):  
Aleksandra Balliu ◽  
Aaltje Roelofje Femmigje Strijker ◽  
Michael Oschmann ◽  
Monireh Pourghasemi Lati ◽  
Oscar Verho

<p>In this preprint, we present our initial results concerning a stereospecific Pd-catalyzed protocol for the C3 alkenylation and alkynylation of a proline derivative carrying the well utilized 8‑aminoquinoline directing group. Efficient C–H alkenylation was achieved with a wide range of vinyl iodides bearing different aliphatic, aromatic and heteroaromatic substituents, to furnish the corresponding C3 alkenylated products in good to high yields. In addition, we were able show that this protocol can also be used to install an alkynyl group into the pyrrolidine scaffold, when a TIPS-protected alkynyl bromide was used as the reaction partner. Furthermore, two different methods for the removal of the 8-aminoquinoline auxiliary are reported, which can enable access to both <i>cis</i>- and <i>trans</i>-configured carboxylic acid building blocks from the C–H alkenylation products.</p>


2019 ◽  
Author(s):  
Ming Shang ◽  
Karla S. Feu ◽  
Julien C. Vantourout ◽  
Lisa M. Barton ◽  
Heather L. Osswald ◽  
...  

<div> <div> <div> <p>The union of two powerful transformations, directed C–H activation and decarboxylative cross-coupling, for the enantioselective synthesis of vicinally functionalized alkyl, carbocyclic, and heterocyclic compounds is described. Starting from simple carboxylic acid building blocks, this modular sequence exploits the residual directing group to access more than 50 scaffolds that would be otherwise extremely difficult to prepare. The tactical use of these two transformations accomplishes a formal vicinal difunctionalization of carbon centers in a way that is modular and thus amenable to rapid diversity incorporation. A simplification of routes to known preclinical drug candidates is presented along with the rapid diversification of an antimalarial compound series. </p> </div> </div> </div>


1977 ◽  
Vol 18 (20) ◽  
pp. 1761-1764 ◽  
Author(s):  
H. Numan ◽  
C.B. Troostwijk ◽  
J.H. Wieringa ◽  
Hans Wynberg

1989 ◽  
Vol 42 (1) ◽  
pp. 17-29 ◽  
Author(s):  
Tomoya Kitazume ◽  
Takeshi Ohnogi ◽  
Jenq Tain Lin ◽  
Takashi Yamazaki ◽  
Keizo Ito

2021 ◽  
Vol 6 (31) ◽  
pp. 7912-7918
Author(s):  
Ekaterina Lerman ◽  
Shlomo Levinger ◽  
Amnon Albeck

Synlett ◽  
2020 ◽  
Vol 32 (01) ◽  
pp. 45-50
Author(s):  
Udo Nubbemeyer ◽  
Analuisa Nava ◽  
Lukas Trippe ◽  
Andrea Frank ◽  
Lars Andernach ◽  
...  

AbstractStarting from methyl cycloheptatrienyl-1-carboxylate, 6-acylation was successfully achieved employing glutaryl chloride in the presence of AlCl3 under controlled reaction conditions to furnish keto carboxylic acid product. After protection of this keto carboxylic acid as tert-butyl ester, reagent-controlled enantioselective reductions delivered configuration-defined methyl-6-hydroxylalkyl cycloheptatriene-1-carboxylates with up to 80% ee. Whereas simple NaBH4 reduction of the keto carboxylic acid and subsequent lactonization afforded a methyl-6-tetrahydropyranonyl cycloheptatriene-1-carboxylate. Resolution using chiral HPLC delivered the product enantiomers with up to >99% ee Finally, ECD analyses enabled structure elucidation. The products are used as key intermediates in enantioselective 6,11-methylene-lipoxin B4 syntheses.


2022 ◽  
Author(s):  
Zhi-Gang Yin ◽  
Xiong-Wei Liu ◽  
Hui-Juan Wang ◽  
Min Zhang ◽  
Xiong-Li Liu ◽  
...  

A highly efficient synthesis of structurally diverse ortho-acylphenol–diindolylmethane hybrids 3 using carboxylic acid-activated chromones as versatile synthetic building blocks is reported here for the first time, through 1,4-nucleophilic addition and followed by a decarboxylation and pyrone ring opening reaction process.


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