First Total Synthesis of Bauerine C

The first total synthesis of Bauerine C, a unique indoloquinazoline alkoloid, has been achieved from readily available 2,3‐dichloroaniline. The key step is the Japp–Klingmann condensation between 2,3‐dichloroaniline and ethyl‐2‐acetyl‐5‐phthalimido pentanoate to get 3‐[(2,3‐dichlorophenyl)‐hydrozono]‐pipiridin‐2‐one, which cyclizes to 7,8‐dichloro‐2,3,4,9‐tetrahydro‐β‐carbolin‐1‐one, which can be methylated by dimethyl sulphate to give 7,8‐dichloro‐9‐methyl 2,3,4,9‐tetrahydro‐β‐carbolin‐1‐one. This N‐methyl derivative is then subjected to dehydrogenation with 2,3‐dichloro‐5,6‐dicayano‐1,4‐benzoquinone (DDQ) to give the target compound Bauerine C.     

First Total Synthesis of (±)-13-Hydroxyneocembrene

First total synthesis of (±)-13-hydroxyneocembrene ( 1 ), starting from 6-methyl-5-hepten-2-one ( 6 ) and geraniol ( 7 ), is described. The key steps are (i) the addition of sulfur-stabilized carbanion 12 to aldehyde 9 , (ii) the synthesis of 18 by using phase-transfer catalyzed coupling reaction, and (iii) low-valent titanium-induced intramolecular coupling of oxo aldehyde 3 to afford the target molecule after the final deprotection.     

(±)-Sinaiticin的首次全合成

首次完成了黄酮木脂素 (± ) -Sinaiticin的全合成 ,通过 9步反应 ,总产率为 1 3.4% ,cis-6发生差向异构化转化为 trans-7,氧化偶联为关键步骤 .     

Total Synthesis of (-)-Maytansinol

A total synthesis of maytansinol (1) was achieved, in a convergent way, using (3S,6S,7S)-aldehyde 4 and (S)-p-tolyl sulfoxide 3 as fragments. When the anion of 3 was condensed with aldehyde 4, some induction at C(10) was observed (60% de), giving the C(1)-N(19)-open-chain compound 7, after thermal elimination of sulfinate. Pure E/E stereochemistry of the 11,13-diene was obtained. Selective modifications of the functionalities permitted macrocyclization and further elaboration to maytansinol.     

Phebaclavin A和C的全合成研究

Phebaclavin A （1） and C （2） were synthesized in 60% and 58% total yields over 5 steps from commercially available starting meterials respectively. The synthesis feature was usage of the Wittig reaction twice and solvent-free cyclizing reaction as the key steps.     

Total synthesis of (-)-tirandamycin C

Tirandamycin C is a newly isolated member of the tetramic acid family natural products. We described herein the first enantioselective synthesis of natural (-)-tirandamycin C, the postulated biosynthetic precursor of other members of this family. The highly stereoselective (>15:1) mismatched double asymmetric γ-stannylcrotylboration reaction of aldehyde 8 with crotylborane reagent (R)-E-9 was utilized to access the key anti,anti-stereotriad 18.     

Total Synthesis of (-)-Muscoride A

The recently isolated cyanobacterium metabolite muscoride A was synthesized in 15 steps and in 4.3% overall yield. Novel structural features of this peptide antibiotic include the presence of a threonine-derived bioxazole core and an N-(1,1-dimethyl)allyl ("reverse prenyl") valine residue. In the context of our synthesis, efficient new strategies for the preparation of these segments were developed. The synthesis of two epimers of muscoride A allowed the unambiguous assignment of the relative and absolute configuration of the natural product by NMR and optical rotation analyses.     

The First Total Synthesis of (±)-3′, 7-Dihydroxy-4′-methoxyflavan

The first total synthesis of (±)-3', 7-dihydroxy-4'-methoxyflavan, a naturally occurring flavan, was described.The key step is the cyclization of 1, 3-diaryl-1-propanol by BF3·Et2O.     

Total Synthesis of (-)- and (+)-Balanol(1)

Two total syntheses of the potent protein kinase C inhibitory fungal metabolite balanol are described. In the first approach, the core aminohydroxyazepane subunit was prepared in racemic form by stereospecific functionalization of N-benzyl-epsilon-caprolactam. Resolution prior to coupling to the benzophenone subunit provided access to both enantiomers of balanol. In the second approach, an efficient silicon-mediated cyclization of (2S,3R)-3-hydroxylysine followed by reduction provided the azepane subunit in enantiomerically pure form. The sterically congested benzophenone subunit was assembled from two highly substituted aromatic precursors by way of an anionic homo-Fries rearrangement.     

First Total Synthesis of the (±)-Preverecynarmin

The preverecynarmin(12), (+)-(1E,3E,7E,11E)-cembra-3,7,11-tetraen-6yl acetate,was first isolated in 1990 from both Armina maculata and its prey,the pennatulacean coral Veretillum cynomorium with other there briarane diferpenoids and cembene-C((1E,3E,7E,11E)-cembra-l,3,7,11-tetraen¹. As far as we known, the bioactive test and total synthesis of ¹² have not been reported yet. Herein we wish to describe the first total synthesis of (±)-preverecynarmin (12).     

Total synthesis of (-)-sessilifoliamide C and (-)-8-epi-stemoamide

A convergent route featuring [3,3]-sigmatropic rearrangements of a linchpin azepinopyrrolidine served to install two of the four contiguous stereocenters present in the tricyclic Stemona alkaloids sessilifoliamide and stemoamide. In addition to the first total synthesis of (-)-sessilifoliamide C, a potential biosynthetic relationship between the sessilifoliamides and previously reported Stemona alkaloids is presented.     

A Formal Total Synthesis of (-)-Brevisamide

A formal total synthesis of (−)-brevisamide has been achieved. The synthetic approach highlights a chemoselective asymmetric dihydroxylation and a one-pot Fraser-Reid epoxidation/PMB protection reaction sequence.     

Total synthesis of (-)-N-methylwelwitindolinone C isothiocyanate

We report the first total synthesis of (-)-N-methylwelwitindolinone C isothiocyanate. Our route features a number of key transformations, including an indolyne cyclization to assemble the [4.3.1]-bicyclic scaffold, as well as a late-stage intramolecular nitrene insertion to functionalize the C11 bridgehead carbon en route to the natural product.     

Total synthesis of (-)-senepodine G and (-)-cermizine C

An efficient, stereospecific synthesis of the alkaloids senepodine G (2) and cermizine C (1) has been completed using the BF3.Et2O-promoted stereospecific addition of Me2CuLi to alpha,beta-unsaturated lactam 6 to provide lactam 3, the addition of MeMgBr followed by HCl to convert 3 to senepodine G (2) (six steps, 40% overall yield), and the stereospecific NaBH4 reduction of 2 to give cermizine C (1) (seven steps, 40% overall yield).     

13-甲氧基-6-羟基钩勿烷-5,8,11,13-四烯-7-酮的首次全合成

以α-环柠檬醛(2)为A环合成子,以间甲氧基苄基氯(3)为C环合成子,经缩合及分子内环化反应得关键中间体6.经1H NMR测试发现化合物6为全顺式结构.化合物6经氧化得双羰基化合物7.将7用t-BuOK/t-BuOH处理后得到烯醇式结构的化合物8.最后将异丙基通过Fride1-Crafts反应一步引入得到目标产物1.     

Total synthesis of (-)-disorazole C1

The antimitotic natural product disorazole C1 was isolated in 1994 from the fermentation broth of the myxobacterium Sorangium cellulosum. We have developed a highly convergent and stereoselective total synthesis of this compound which establishes its relative and absolute configuration. Key features of our synthesis include a highly convergent strategy and selective functional group manipulations that minimize decomposition of the sensitive polyene macrodiolide.