Total synthesis of farylhydrazones A and B

Herein we report a concise total synthesis of farylhydrazones A and B, naturally occurring phenylhydrazones recently isolated from cultures of the Cordyceps-colonizing fungus Isaria farinosa, completed in six and five steps respectively starting from 2-nitrobenzoic acid. The synthesis is completely scalable, and highly convergent—making it adaptable for the preparation of analogues and investigation into the biological activity of these unique natural products.     

Total synthesis of (−)-petrosiol E

(−)-Petrosiol E, a metabolite of sponge Petrosia strongylata, has been synthesized in 32% overall yield from cheap natural d-xylose in 10 steps. Our strategy provides an efficient way for the total synthesis of other petrosiol members, featuring the three contiguous stereogenic centers are easily constructed from d-xylose chiral template.     

Total synthesis of naturally occurring 5,6,7- and 5,7,8-trioxygenated coumarins

The synthesis of five naturally occurring polyoxygenated coumarins is described. It concerns two 5,6,7-trioxygenated coumarins, i.e., 6-hydroxy-5,7-dimethoxycoumarin (fraxinol) 1 and 5,6,7-trimethoxycoumarin 2, and three 5,7,8-trioxygenated coumarins, i.e., 8-hydroxy-5,7-dimethoxycoumarin (leptodactylone) 3, 5,7,8-trimethoxycoumarin 4 and 8-(3-methyl-2-butenyloxy)-5,7-dimethoxycoumarin (artanin) 5. Key feature of the synthetic pathway is the synthesis of suitable tetraoxygenated benzaldehydes, which are then converted to the corresponding coumarins via a Wittig reaction.     

Advances in Total Synthesis of Some 2,3,5‐Trisubstituted Tetrahydrofuran Natural Products

2,3,5‐Trisubstituted tetrahydrofuran moiety is ubiquitous in natural products. These have served as appealing candidates for total synthesis due to their varied bio‐ and pharmaceutical activities. This tutorial review delineates the ingenious efforts by many researchers in the total synthesis of selected natural products based on a common 2,3,5‐trisubstituted tetrahydrofuran core structure. Many of the syntheses display nuanced interplay between new methods and the ingenuity of planned strategies achieved through catalysis or cascade chemistry. In some cases, the chiron approach has come quite handy, wherein the structural features and the stereochemistry in select molecules could map well with naturally available starting materials. This compilation also aims to enhance the diversity space based on these natural products and further interest in sustainable total synthesis.     

Total synthesis of (−)-muricatacin

A total synthesis of (−)-muricatacin has been achieved using a commercially available starting material and our furan approach to oxacyclic systems, the proven scope of which is thus broadened.     

Total synthesis of cyercene A and the biomimetic synthesis of (±)-9,10-deoxytridachione and (±)-ocellapyrone A

This paper summarises our detailed study towards the biomimetic synthesis of the complex polypropionate derived natural product (±)-9,10-deoxytridachione. A previous study based on the elaboration of functionalised γ-pyrones allowed us to synthesise cyercene A. The same efficient methodology has been applied for the elaboration of a more complex fully conjugated γ-pyrone polyene. Our approach centred on a key tandem Suzuki-coupling/electrocyclisation reaction, which supports a possible biosynthetic pathway for this class of natural products. A related compound was obtained during our studies, which we identified as the correct structure of ocellapyrone A.     

Total Synthesis of Chatancin

As an antagonist of the platelet activating factor , chatancin ( 1 ), which is isolated from a soft coral, is of potential therapeutic use. The first total synthesis [Eq. (1)] of this structurally unusual diterpene in racemic form is described along with the formal total syntheses of natural (+)-chatancin as well as unnatural (−)-chatancin.     

Total synthesis of (−)-Englerin A

A novel and efficient total synthesis of Englerin A is reported. The synthesis featured an intramolecular olefin metathesis ring closure reaction and a highly stereoselective oxygen bridge formation induced by an iodonium ion. This strategy can be used for the synthesis of natural products Englerin A and Englerin B and can provide flexibility in the preparation of various 9-substituted analogues of Englerin A for further structure–activity relationship studies.     

Total synthesis of cyclopiamide A and speradine E

Described is a total synthesis of the related alkaloids, cyclopiamide A and speradine E, via a unified strategy that also delivers the natural product aspergilline A. Key steps include metal-free conversion of a malonyl chloride and propargylamine to an intermediate pyrrolinone and a palladium catalyzed decarboxylation/aromatization sequence that delivers the requisite tetracyclic core.     

Total Synthesis of Sch 725674

A concise total synthesis of the macrolactone natural product Sch 725674 is accomplished starting from commercially available 2-deoxy-d-ribose. Pivotal reactions employed in the synthesis include the addition of 4-pentenylmagnesium bromide to the lactol derived from 2-deoxy-d-ribose, olefin cross metathesis and Yamaguchi macrolactonization.     

Total Synthesis of Sanglifehrin A

The immunosuppressive agent sanglifehrin A has been prepared for the first time by total synthesis. The construction of the macrocyclic unit of the target molecule was achieved through a selective intramolecular Stille coupling, and the spirolactam unit by Paterson–aldol reactions. The final steps involve an intermolecular Stille coupling and the opening of the internal acetal unit. This convergent synthesis opens the way for the synthesis of libraries of novel sanglifehrin analogues for biological screening.     

Concise and Efficient Total Syntheses of Alkannin and Shikonin

Two enantiomic natural products with wound-healing properties , alkannin ( 1 ) and shikonin ( 2 ), are accessible by a short and efficient total synthesis. The success was achieved by a novel protecting system for masking of 5,8-dihydroxy-1,4-naphthoquinones (naphthazarins) and a highly stereoselective ketone reduction.     

Total synthesis,reactivity, and structural clarification of lindenatriene

The synthesis of lindenatriene (1) and iso-lindenatriene (12) were achieved, along with the des-hydroxy model compounds (10 and 18, respectively), and compared to reported ¹H NMR spectra in the literature (1a and 10a). These comparisons clarify the correct initial assignment of lindenatriene (1) as well as its instability and propensity to isomerize into the more thermodynamically favored iso-lindenatriene (12).     

Total Synthesis of the Proposed Structure of (+)-Tolyporphin A O,O-Diacetate

Four monocyclic precursors were assembled in the total synthesis of the proposed structure 1 - A of (+)-tolyporphin A O,O-diacetate (X=Ac). Comparison of the spectroscopic data demonstrated that synthetic tolyporphin O,O-diacetate did not match the O,O-diacetate prepared from natural (+)-tolyporphin A (X=H), calling for a structural revision of this class of natural products. On the basis of a series of NMR experiments including synthetic intermediates, the structure of tolyporphin A is concluded to be 1 - B , in which the configurations of quaternary centers C7 and C17 are opposite to those in the originally proposed structure.     

Recent progress toward the total synthesis of humulanolides

The humulanolides are a series of sesquiterpene lactones, most of which have unique and challenging structure. The humulanolides have exhibited anticancer activity. The combinations of fascinating structural motifs and promising pharmacological properties have prompted significant interest in the synthetic community. In this review, we provide a summary of recent progress regarding the total synthesis of humulanolides.     

Total synthesis of anithiactins A-C and thiasporine A

The total syntheses of anithiactins A-C (1–3) and thiasporine A (4) have been achieved in good overall yields. The key reaction in the synthetic sequence was the Suzuki-Miyaura cross-coupling between 2-aminophenylboronic acid hydrochloride and methyl 2-bromothiazole-4-carboxylate forming the common intermediate methyl 2-(2-aminophenyl)thiazole-4-carboxylate (8), which could be further transformed by hydrolysis, alkylation, and aminolysis to give the four title natural products. This work represents the first total synthesis of anithiactin B (2) and C (3).     

Total synthesis of modified pentapeptide,caldoramide

Total synthesis of modified pentapeptide, caldoramide, a cytotoxic linear pentapeptide from the marine cyanobacterium Caldora penicillate is described. Notable features of the route include the efficient preparation of three key fragments and final assembly to the natural product via sequential amide couplings. The spectral data of the synthetic compound was found to be in comparison with that of the isolated natural product.     

Total synthesis of (+)-bongkrekic acid

Total synthesis of bongkrekic acid, an important apoptosis inhibitor, has been accomplished. The strategy includes inexpensive starting materials, asymmetric alkylation, anionic allyl coupling and oxidative manipulations. This process would provide a sufficient amount of bongkrekic acid and its analogues.     

Total Syntheses of Vancomycin and Eremomycin Aglycons

Controlling the elements of planar and axial chirality are the principal challenges in the synthesis of the aglycon of vancomycin. Vancomycin is the prototypical member of the glycopeptide family of antibiotics which are effective for the treatment of infections by methicillin-resistant Staphylococcus aureus. The first total syntheses of the vancomycin and eremomycin aglycons provide insight into the influence of structure on kinetic and thermodynamic control of atropselective macrocyclizations.     

6-Oxodendrolasinolide的全合成

以香叶醇(2)和异戊烯醇(5)为起始原料, 经过12步反应, 以5.6%的总收率完成了倍半萜内酯6-Oxodendrolasinolide (1)的全合成. 其关键步骤包括乙烯基二噻烷(7)的负离子与烯丙基氯(4a)的区域选择性烷基化反应和Corey's氧化内酯化反应.