Synthesis of the molecular hybrid inspired by Largazole and Psammaplin A

One important class of HDAC (histone deacetylation enzymes) inhibitors is the sulfur-containing marine natural products with structural diversity. Inspired by two structurally distinguishing examples, Largazole and Psammaplin A, which possess macrocyclic depsipeptide and simple linear amide scaffold respectively, we designed one novel molecular hybrid by replacing the alkene moiety in Largazole with a semirigid amide bond. This hybrid compound has been synthesized from l-malic acid in 10 steps with an overall yield of 7%. The preliminary biological assays suggest that the replacement of trans olefin moiety with amide bond will lead to an unbeneficial effect on the inhibition against HDACs.     

Efficient and stereoselective installation of isoquinoline: formal total synthesis of cortistatin A

The highly stereoselective attachment of isoquinoline onto the steroidal framework of cortistatin A has been achieved. Our strategy features a Ce-mediated nucleophilic addition of an isoquinoline unit to the sterically congested ketone followed by formation of the phenyl thiocarbamate, and subsequent stereoselective radical reduction. The new method results in a formal total synthesis of cortistatin A.     

First total synthesis of natural products cajanolactone A and cajanonic acid A

First total synthesis of cajanolactone A and cajanonic acid A has been achieved through steps of anion–anion condensations,cyclization,Williams etherification,selective demethylation,1 3-sigmatropic rearrangement and hydrolysis.This work provides an efficient method for future cajanonic acid A derivatives synthesis.     

(+)-Sorangicin A: evolution of a viable synthetic strategy

An effective, asymmetric total synthesis of the antibiotic (+)-sorangicin A (1) has been achieved. Central to this venture was the development of first- and second-generation syntheses of the signature dioxabicyclo[3.2.1]octane core, the first featuring chemo- and stereoselective epoxide ring openings facilitated by a Co₂(CO)₆-alkyne complex, the second involving a KHMDS-promoted epoxide ring formation/opening cascade. Additional highlights include effective construction of the dihydro- and tetrahydropyran ring systems, respectively, via a stereoselective conjugate addition/α-oxygenation protocol and a thioketalization/hydrostannane reduction sequence. Late-stage achievements entailed two Julia-Kociénski olefinations to unite three advanced fragments with high E-stereoselectivity, followed by a modified Stille protocol to introduce the Z,Z,E trienoate moiety, thereby completing the carbon skeleton. Mukaiyama macrolactonization, followed by carefully orchestrated Lewis and protic acid-promoted deprotections that suppressed isomerization and/or destruction of the sensitive (Z,Z,E)-trienoate linkage completed the first, and to date only, total synthesis of (+)-sorangicin A (1).     

A novel and practical synthetic route for the total synthesis of lycopene

A novel route for the total synthesis of lycopene 1 is described. The synthesis is based on: (i) a condensation between 4,4-dimethoxy-3-methylbutanal 4 and methylenebisphosphonic acid tetraethyl ester 5, leading to the C6-phosphonate 6, followed by (ii) a modified Wittig-Horner reaction between 6 and 6-methyl-5-hepten-2-one 7 producing dimethoxy-3,5,9-triene 8, and (iii) another modified Wittig-Horner reaction between C15-phosphonate 2 and C10-triene dialdehyde 3 producing all-E-lycopene. The synthetic steps are easily operated and practical for the large-scale production.     

First total synthesis of paecilodepsipeptide A

The first total synthesis of paecilodepsipeptide A is reported.A convergent,flexible strategy employing peptide chemistry and culminating in macrolactamisation is described.The previously reported structure of compound is confirmed.     

天然产物goodyeroside A的全合成研究

以5-(S)-(d-盖氧基)-2(5H)-呋喃酮为起始原料．对具有肝保护活性的天然产物goodyeroside A进行了全合成研究。将合成所得目标产物的比旋光值及光谱数据与天然产物的数值相比较，两者一致，证明两者的结构与构型相同。     

Efficient Synthesis of Octalone

A highly efficient and convergent approach for the synthesis of octalone 1, the focal intermediate for the synthesis of several sesquiterpenoids, was developed based on the cationic cyclization strategy of the functionalized oxabicyclic template 5.     

Total syntheses of melinonine-E and strychnoxanthine: Evolution of the synthetic strategy enabled by novel method development

In this full account, the evolution of a synthetic strategy was detailed from a nitroso-ene cyclization to an aza-Wacker reaction for ring construction in the syntheses of melinonine-E and strychnoxanthine. The aza-Wacker cyclization to form the bridged ring was successfully developed and applied in the first asymmetric syntheses of melinonine-E and strychnoxanthine in 5–6 steps from a readily available chiral lactone. The proposed biogenesis of these two rare β-carbolinium alkaloids was revised based on their absolute configurations. Moreover, the substrate scope of the aza-Wacker cyclization demonstrated its potential for accessing various bridged ring skeletons. The mechanistic investigation established that the profound effect of the N-substituent on the amide was crucial to the success of the cyclization via the tunable amidopalladation pathway.     

Total synthesis of pyripyropene A

The total synthesis of pyripyropene A, a potent ACAT2 inhibitor with high isozyme selectivity, was completed. Key features of the synthetic strategy include Ti(III)-mediated radical cyclization and Peterson olefination for the construction of the AB ring segment and stereoselective dihydro-γ-pyrone formation (C-ring). The total synthesis provided pyripyropene A in 5.3% overall yield over 17 steps.     

Efficient total synthesis of (+)-curcuphenol via asymmetric organocatalysis

The catalytic enantioselective synthesis of (+)-curcuphenol is described herein. This approach involves the use of an organocatalytic alkylation of m-anisidine, a diazotation/Sandmeyer reaction of the amine and a Negishi-type coupling with dimethylzinc. This versatile strategy allows for the rapid synthesis of other members of this class of natural products.     

Stereoselective total synthesis of cochliomycin A

A convergent and stereoselective synthesis of cochliomycin A, a 14-membered resorcyclic acid lactone, based on chiron approach is described. The key reactions involved olefin cross-metathesis and sodium hydride promoted one-pot intramolecular lactonization. l-Arabinose was used as a chiral pool material for the construction of the key fragment.     

Total Synthesis of (±)-Celaphanol A

Celaphanol A was a diterpene isolated from the stems of Celastrus stephanotifolius1, which have been the subject of continued and growing interest, due to the range of biological activities shown by many members of this family2. Some have been used in traditional medicine3 or as a stimulant4 from ancient times. In order to further study the relationship between the structure and biological activity of the diterpene compound and as an extension of diterpenoid synthesis in our laboratory5, 6, …     

Toward the natural didemnaketal A: total synthesis of the isomer of didemnaketal A

The total synthesis of isomer of didemnaketal A was achieved in 26 steps. The position of esters is switched at C7 and C8 with respect to their proposed position in natural didemnaketal A, which shows potent anti-HIV activity but so far has not been synthesized in the laboratory. Structural analysis of synthetic isomer of didemnaketal A indicates that the esters at C7 and C8 are correctly assigned, suggesting that the problems for the structural reassignment of natural didemnaketal A lie elsewhere.     

A New Efficient Synthesis of Bisphenol A Diether Bis-imidazoles and Bis-benzimidazoles

ThewiderangeofpotentialapplicationsofbisphenolAdietherhis-imidazolesandbisbenzinddazolesinmedicinal,pesticideandbioinorganic,bioorganic,biondmeticandsupramolecularchemistfyleadourspecialinteresttodeveloptheirefficientsyntheses.Inthepreviouspaper,wereportedthesynthesisofbisphenolAdietherhis-imidazolesandhis-benzimidazoles3a-cbyhydroxyethylation,tosylationandimidazolylationthree-stepreactionsfromcommercialbisphenolA,imidazoleanditd.,i..ti..,i.HerewewillreportanewsynthesisofbisphenolAdietherhis-…     

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.     

First stereoselective total synthesis of Neocosmosin A: a facile approach

First stereoselective concise synthesis of Neocosmosin A, with in vitro binding affinity for human opioid and cannabinoid receptors, has been reported using readily available starting materials such as methylacetoacetate, cyclohexanone, and homoallyl alcohol involved in the key transformations. There are three fragments involved in the synthesis of target molecule, bearing acid functionality, (R)-pent-4-en-2-ol, and Weinreb amide which are synthesized in four, eight, and three steps, respectively. Then the fragments were coupled in four steps to yield the target molecule in an overall yield of 28.6%.     

Total synthesis of emericellamides A and B

The total synthesis of emericellamides A and B is reported. A convergent, flexible strategy employing peptide chemistry, asymmetric alkylations, and culminating in macrolactamization is described. The previously reported structure of both compounds is confirmed.     

Towards the real didemnaketal A: total syntheses of two C-21 stereoisomers of the proposed didemnaketal A

Two isomers (3 and 4) with a configuration at C-21 opposite to that proposed for didemnaketal A were synthesized through a process in which the longest linear sequence involved 29 steps. Comparative NMR analysis of these isomers and natural didemnaketal A suggests the possibility of misassignments at other stereocenters in the proposed structure of didemnaketal A.