A Modular Approach to Marine Macrolide Construction. 4. Assembly of C36−C51 and C29−C44 Building Blocks and Evaluation of Key Coupling Reactions Targeting Spongistatin 1 (Altohyrtin A)

2007 ◽  
Vol 9 (4) ◽  
pp. 719-722 ◽  
Author(s):  
Stephane Ciblat ◽  
Jungchul Kim ◽  
Catherine A. Stewart ◽  
Jizhou Wang ◽  
Pat Forgione ◽  
...  
2009 ◽  
Vol 74 (5) ◽  
pp. 651-769 ◽  
Author(s):  
Alain Braun ◽  
Il Hwan Cho ◽  
Stephane Ciblat ◽  
Dean Clyne ◽  
Pat Forgione ◽  
...  

Enantioselective approaches to the construction of four complex building blocks of the structurally intricate marine macrolide known as spongistatin 1 are presented. The first phase of the synthetic effort relies on a practical approach to a desymmetrized, enantiomerically pure spiroketal ring system incorporating rings A and B. Concurrently, the C17–C28 subunit, which houses one-fifth of the stereogenic centers of the target in the form of rings C and D, was assembled via a composite of stereocontrolled aldol condensations. Once arrival at the entire C1–C28 sector had been realized, routes were devised to provide two additional highly functionalized sectors consisting of C29–C44 and C38–C51. A series of subsequent transformations including cyclization of the E ring and hydroboration to afford the B-alkyl intermediate for the key Suzuki coupling to append the side chain took advantage of efficient stereocontrol. Ultimately, complete assembly and functionalization of the western EF sector of spongistatin was thwarted by an inoperative Suzuki coupling step intended to join the side chain to the C29–C44 sector, and later because of complications due to protecting groups, which precluded the complete elaboration of the late stage C29–C51 intermediate.


2019 ◽  
Author(s):  
Victor Bloemendal ◽  
Floris P. J. T. Rutjes ◽  
Thomas J. Boltje ◽  
Daan Sondag ◽  
Hidde Elferink ◽  
...  

<p>In this manuscript we describe a modular pathway to synthesize biologically relevant (–)-<i>trans</i>-Δ<sup>8</sup>-THC derivatives, which can be used to modulate the pharmacologically important CB<sub>1</sub> and CB<sub>2</sub> receptors. This pathway involves a one-pot Friedel-Crafts alkylation/cyclization protocol, followed by Suzuki-Miyaura cross-coupling reactions and gives rise to a series of new Δ<sup>8</sup>-THC derivatives. In addition, we demonstrate using extensive NMR evidence that similar halide-substituted Friedel-Crafts alkylation/cyclization products in previous articles were wrongly assigned as the para-isomers, which also has consequence for the assignment of the subsequent cross-coupled products and interpretation of their biological activity. </p> <p>Considering the importance of the availability of THC derivatives in medicinal chemistry research and the fact that previously synthesized compounds were wrongly assigned, we feel this research is describing a straightforward pathway into new cannabinoids.</p>


2005 ◽  
Vol 3 (13) ◽  
pp. 2431 ◽  
Author(s):  
Ian Paterson ◽  
David Y.-K. Chen ◽  
Mark J. Coster ◽  
José L. Aceña ◽  
Jordi Bach ◽  
...  

2021 ◽  
Vol 25 ◽  
Author(s):  
Maysa Ilamanova ◽  
Maxim Mastyugin ◽  
Christian Schäfer ◽  
Anne Kokel ◽  
Béla Török

: This account provides a broad overview of the application of solid metal catalysts in synthetic chemistry with a focus on the synthesis of medicinally important scaffolds or building blocks. Heterogeneous catalysis is a fundamental contributor to green or sustainable synthesis. Despite this, many synthetic chemists overwhelmingly focus on homogeneous methods, and due to their unfamiliarity with solid catalysts, many would not consider using them. The primary purpose of this work is to bring solid catalysts and their application possibilities to the attention of synthetic chemists in a format that focuses on reactions, thus building a bridge between the two sides for the benefit of sustainable applications and, eventually, the whole society. The two major parts of this account describe the common types of solid metal catalysts and the applications of these catalysts in sustainable synthesis. The first part gives an overview of the major types of solid metal catalysts, including common hydrogenation catalysts to metal nanoparticles. The second and more extensive part illustrates the use of these catalysts in a thematic order based on reaction types, including hydrogenation, hydrogenolysis, oxidation, metathesis, cross-coupling reactions, and hydroformylation.


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