1,1′-联-2-萘酚的合成新进展

1,1′-联-2-萘酚是具有C2轴不对称联芳香族化合物,已在不对称合成、分子识别、新材料合成等领域有着广泛的应用。文章综述了1,1′-联-2-萘酚的基本性能、应用以及国内外最常用与最新的合成方法。     

The first total synthesis of the natural product angoluvarin

The total synthesis of angoluvarin, a member of the dihydrochalcone family of natural products, is reported. Starting with 2-bromophenol, the synthesis was accomplished in eight steps with an overall yield of 2%. This represents the first reported synthesis of angoluvarin.     

Synthesis and chemistry of the ionophore antibiotic tetronasin

Studies towards the synthesis and biosynthesis of tetronasin, an acyltetronic acid ionophore are described, together with an account of some novel methodology which is more widely applicable for the synthesis of other acyltetronic acids.     

木脂素类化合物的全合成研究

综述了本研究小组近几年在木脂素全合成研究中取得的新进展。主要包括三部分：通过β-酮酸酯偶联反应来合成去甲二氢愈创木酸及多种其它类型木脂素;通过氧化银偶联和DDQ合环首次合成黄酮木脂素(±)-Sinaiticin;通过Sharpless不对称双羟化为关键步骤首次手性合成1,4-苯并二氧六环类新木脂素。     

Trapping of a phosphazide intermediate in the Staudinger reaction of tertiary phosphines with azides and its application to the synthesis of analogs of the marine alkaloid midpacamide

A new method based on the reaction of an E-phosphazide, an intermediate in the Staudinger reaction between triphenylphosphine with an azide, with heterocumulenes allows the one-pot, two-component synthesis of a number of analogs of the pyrrole-imidazole marine alkaloid midpacamide. The procedure, which involves sequential treatment of the appropriate α-azido ester with triphenylphosphine and isothiocyanate leads to the thiohydantoin product after aqueous workup. The cyclization conditions can also be adapted to the synthesis of hydantoins by using isocyanates.     

Solid catalysts for the production of fine chemicals: the use of natural phosphate alone and doped base catalysts for the synthesis of unsaturated arylsulfones

The inexpensive natural phosphate, both alone and doped with potassium fluoride, is a new basic catalyst for the synthesis of α,β-unsaturated arylsulfones. Activation by water and benzyltriethylammonium chloride has also been investigated. When using an ammonium salt, natural phosphate doped with potassium fluoride is an excellent solid support for the synthesis of α,β-unsaturated arylsulfones, leading to excellent yields in a few minutes.     

Total synthesis of laulimalide: assembly of the fragments and completion of the synthesis of the natural product and a potent analogue

Herein, we present a full account of our efforts to couple the northern and the southern building blocks, the synthesis of which were described in the preceding paper, along with the modifications required to ultimately lead to a successful synthesis of laulimalide. Key highlights include an exceptionally efficient and atom-economical intramolecular ruthenium-catalyzed alkene-alkyne coupling to build the macrocycle, followed by a highly stereoselective 1,3-allylic isomerization promoted by a rhenium complex. Interestingly, the designed synthetic route also allowed us to prepare an analogue of the natural product that possesses significant cytotoxic activity. We also report a second generation route that provides a more concise synthesis of the natural product.     

Effect of the synthesis conditions on the size of magnetite nanoparticles produced by high-temperature reductive hydrolysis

A study was made into the effect of the conditions (synthesis temperature, water content, iron salt(III) concentration, and nature of precipitant) of the synthesis of magnetite nanoparticles by high-temperature reductive hydrolysis of iron(III) salts in an ethylene glycol medium on their size and morphology. It was shown that is basically possible to carry out the direct synthesis of spherical particles with an average size of 55–170 nm while varying synthesis conditions. The obtained particles were characterized by X-ray powder diffraction analysis, and their magnetic properties were explored. The synthesized particles are ferrimagnets. The magnetic moments, numbers, and sizes of domains in magnetite particles of various sizes were found.     

Total synthesis of bryostatins: the development of methodology for the atom-economic and stereoselective synthesis of the ring C subunit

Bryostatins, a family of structurally complicated macrolides, exhibit an exceptional range of biological activities. The limited availability and structural complexity of these molecules makes development of an efficient total synthesis particularly important. This article describes our initial efforts towards the total synthesis of bryostatins, in which chemoselective and atom-economical methods for the stereoselective assembly of the ring C subunit were developed. A Pd-catalyzed tandem alkyne-alkyne coupling/6-endo-dig cyclization sequence was explored and successfully pursued in the synthesis of a dihydropyran ring system. Elaboration of this methodology ultimately led to a concise synthesis of the ring C subunit of bryostatins.     

Total synthesis of broussonetine F: the orthoamide Overman rearrangement of an allylic diol

A first total synthesis of broussonetine F from diethyl L-tartrate was achieved. The cornerstone of our synthesis was an orthoamide Overman rearrangement, which provided an allylic amino alcohol with complete diastereoselectivity.     

First total synthesis of phenylpyridine analogues of the antimitotic rhazinilam

The first synthesis of phenylpyridine analogues of rhazinilam and evaluation of these new structures as inhibitors of microtubule disassembly by interaction with tubulin are described. The synthesis is based on such key steps as picolinic metalation, hetero-ring cross-coupling and reduction of an acetyl group to an ethyl group. Elaboration of a quaternary picolinic carbon is one of the challenges of the synthesis. Biological evaluation of compounds bearing a quaternary picolinic carbon showed interactions with tubulin similar to (-)-rhazinilam but at a lower level.     

An efficient synthesis of the 1,6-dioxaspiro[4.4]nonan-2-one motif of the immunosuppressive triterpenoid Phainanoid F

We describe an efficient synthesis of the 1,6-dioxaspiro[4.4]nonan-2-one motif of the immunosuppressive triterpenoid Phainanoid F and its C4 epimer. A furan oxidative spirocyclization for constructing the spiro center was used as the key step. Other important reactions involved Sharpless asymmetric dihydroxylation, Weinreb ketone synthesis and Yamaguchi esterfication. The synthesis was achieved in 11 linear steps with 17.3% overall yield.     

Wallichanol类天然产物ABC环系合成研究

Wallichanol是一类具有独特桥环结构的二萜天然产物.以2-甲基-1,3-环己二酮作为起始原料,通过高立体选择性的Diels-Alder反应和金催化的炔烃碳环化反应构建Wallichanol的ABC三环核心骨架,共七步路线,总收率为42%.该合成工作为Wallichanol类天然产物全合成奠定了研究基础.     

Rhodium-catalyzed direct C-H addition of 3,4-dihydroquinazolines to alkenes and their use in the total synthesis of vasicoline

The inter- and intramolecular couplings of unactivated alkenes to 3,4-dihydroquinazolines with a Rh(I) catalyst are reported. Coupling between olefins and NH-3,4-dihydroquinazoline was found to occur consecutively with heterocycle dehydrogenation in the presence of a Rh(I)/PCy3/HCl catalyst. The reaction was used to develop an effective method for the synthesis of 2-substituted quinazolines through an oxidative workup step. The regiocontrolled synthesis and Rh-catalyzed cyclization of alkene-tethered 3,4-dihydroquinazolines are also described. Applying this method, the second total synthesis of vasicoline was achieved. The key Rh-catalyzed cyclization step was made possible by the use of a rigid bicyclic phosphine ligand. The synthesis further demonstrates a challenging Cu-catalyzed amidation of an ortho-substituted aryl chloride.     

Combinatorial Methods for the Synthesis of Aluminophosphate Molecular Sieves

Automatic dispensing of reagents into autoclave blocks followed by synthesis, isolation, and automated structure analysis with X-ray diffractometry represents an efficient methodology for the combinatorial synthesis of microporous materials. The figure shows a typical diffractogram of as-synthesized AFI-type molecular sieves taken with a CCD camera.     

Utility of the ammonia-free Birch reduction of electron-deficient pyrroles: total synthesis of the 20s proteasome inhibitor, clasto-lactacystin beta-lactone

A new synthesis of the 20S proteasome inhibitor clasto-lactacystin beta-lactone is described. Our route to this important natural product involves the partial reduction of an electron deficient pyrrole as a key step. By judicious choice of enolate counterion, we were able to exert complete control over the stereoselectivity of the reduction/aldol reaction. Early attempts to complete the synthesis by using a C-4 methyl substituted pyrrole are described in full, together with our attempts to promote regioselective elimination of a tertiary alcohol. The lessons learnt from this first approach led us to develop another, and ultimately successful, route that introduced the C-4 methyl group at a late stage in the synthesis. Our successful route is then described and this contains several highly stereoselective steps including a cis-dihydroxylation and an enolate methylation. The final synthesis proceeds in just 13 steps and in 15 % overall yield making it an extremely efficient route to this valuable compound.     

A convergent synthesis of the immunosuppressant FTY720 employing aqueous Wittig chemistry

A short, convergent synthesis of the immunosuppressant FTY720 is described involving the use of 4-hydroxymethylbenzaldehyde as a pivotal intermediate. A double Wittig strategy was developed to connect this dual-functional aldehyde with an alkyl-tether and to a readily available TRIS-derivative leading to an efficient synthesis of the target molecule.     

Studies towards the synthesis of the benzodiazepine alkaloid auranthine

Different approaches towards the synthesis of auranthine have been investigated. A completed synthesis of 3‐[2‐(4‐oxo‐3,4‐dihydro‐quinazolin‐2‐yl)‐3,4‐dihydro‐1H‐benzo[e][1,4]‐diazepine‐2,5‐dione, an auranthine precursor, which after dehydration with 50% propylphophonic acid anhydride solution in ethl acetate and DMA gave a C‐acetyl derivative of aurnathine. Additionally studies towards the synthesis of fused quinazolinones yielded the C‐acetylated pyrido[2,1‐b]quinazolinones or butyric acid derivatives.     

Synthesis of the western half of the lolicines and lolitrems

[reaction: see text] The synthesis of the highly substituted indole portion of the complex tremorgenic natural products lolicine A and B is presented. The Diels-Alder reaction of a quinone monoimine enables the synthesis of an appropriately substituted indole. The key step in the synthesis is a tandem isopropenyl cuprate addition/aldol cyclocondensation which provides the necessary functionality for elaboration to the 2,2,5,5-tetramethyltetrahydrofuran.     

A novel method for the generation of nitrile oxides on solid phase: application to the synthesis of substituted benzopyranoisoxazoles

A solid-phase synthesis of substituted benzopyranoisoxazoles is described. The six-step synthesis features a novel method of generating nitrile oxides on a polymer support followed by an intramolecular 1,3-dipolar cycloaddition with a tethered alkyne for assembly of the benzopyranoisoxazole scaffold. Furthermore, the utilization of single-bead attenuated total reflectance Fourier transform infrared (ATR-IR) microspectroscopy as an essential analytical tool for reaction optimization is highlighted.