Total synthesis of (±)-antofine

An efficient preparation of (±)-antofine is described. The main steps involved in this synthesis are the Horner–Wadsworth–Emmons reaction, the intramolecular Schmidt reaction of an azido aldehyde, and the one-pot deprotection of the N-formyl group, followed by Pictet–Spengler cyclization. The asymmetric hydrogenation of the trisubstituted α,β-unsaturated ester is also explored, however only moderate enantio-control (55% ee) is obtained. Finally, (±)-antofine is prepared in six steps from the phenanthryl aldehyde 5 with an overall yield of 35%.     

Efficient syntheses of streptocarpone and (±)-α-dunnione

An efficient divergent synthesis of both streptocarpone and racemic α-dunnione from lawsone are described. A one-pot, formal [3+2] cyclization to form a furanonaphthoquinone directly provided a common intermediate.     

A facile total synthesis of (±)-α-cuparenone employing diallylation and RCM as key steps

A short and concise total synthesis of α-cuparenone employing one-pot diallylation and RCM as the key steps is described.     

Exploiting the Maitland-Japp reaction: a synthesis of (±)-centrolobine

Application of our one-pot, three-component variation of the Maitland-Japp reaction has led to the formation of a tetrahydropyran-4-one, which was converted in three steps to the antiparasitic and antibiotic natural product (±) centrolobine.     

Sequential pericyclic reaction of ene-diallene: synthesis of (±)-estrone

The one-pot construction of perhydrophenanthrene from an acyclic substrate was achieved via a sequential pericyclic reaction, which involved the in situ generation of ene-diallene species due to Myers' propargyl alcohol-allene transformation. The resulting perhydrophenanthrene derivative could be successfully converted into (±)-estrone.     

Novel total syntheses of (±)-oxerine by intramolecular Heck reaction

Both a three-step and a five-step syntheses of monoterpene alkaloid (±)-oxerine from alcohol 6 have been accomplished. In the second approach, the synthetic efficiency was enhanced by implementing a one-pot protocol (deprotonation/silylation/ alkylation/desilylation). The construction of the cyclopenta[c]pyridine framework was realized by an intramolecular Heck reaction, which should be adaptable for the synthesis of other related monoterpene pyridine alkaloids.     

Efficient syntheses of (±)-hydrangenol, (±)-phyllodulcin and (±)-macrophyllol

In this paper we report on a efficient and flexible synthetic route towards the total syntheses of the dihydrocoumarine derivatives hydrangenol (1), phyllodulcin (1a) and macrophyllol (6b). The syntheses started with a readily available phosphonium salt 2 and suitable modified benzaldehydes 3/3a/3b resulting in 46 to 61% overall yields in three to four-steps sequences. The racemic products could be separated by chiral HPLC. The evidence of the (R)-enantiomer for sweetness could be demonstrated for 1a.     

The first total syntheses of (±)-Preussomerins K and L using 2-arylacetal anion technology

The first syntheses of newly isolated members of the Preussomerin family, Preussomerins K and L, are reported. Key steps include the functionalisation of a 2-arylacetal anion, one-pot Friedel-Crafts cyclisation-deprotection and reductive opening of epoxides.     

First total synthesis of (±)-puyanin and (±)- 4′-O-methylbonannione

A facile approach for the first total synthesis of two naturally occurring geranylated flavonoids, (±)-puyanin 1 and (±)-4′-O-methylbonannione 2 have been obtained with total yield 27% and 21%, respectively. The key steps were regioselective cyclization of geranylated tetrahydroxychalcone and regioselective geranylation of 2, 4, 6-trihydroxy- acetophenone.     

Copper(I)-catalyzed asymmetric alkene aziridination mediated by PhI(OAc)2: a facile one-pot procedure

A facile one-pot procedure for copper-catalyzed PhI(OAc)₂-mediated asymmetric alkene aziridination had been developed. Commercially available PhI(OAc)₂ and sulfonamides were used to generate the nitrene precursors (PhINR) in situ for olefin aziridination. This one-pot procedure had been optimized using 4-nitrobenzenesulfonamide as the nitrene source. With 5 mol % of the chiral copper catalyst, these conditions afforded 94% yield of the isolated product with 75% ee. We had also developed a simple and rapid method to monitor the rate of this one-pot aziridination.     

Total synthesis of (±)-stemonamide, (±)-isostemonamide, (±)-stemonamine, and (±)-isostemonamine using a radical cascade

A total synthesis of (±)-stemonamide and (±)-isostemonamide has been achieved by using a radical cascade that involves two endo-selective cyclizations. (±)-Stemonamine and (±)-isostemonamine are synthesized by chemoselective reduction of (±)-stemonamide and (±)-isostemonamide, respectively.     

A new route to eremophilanes: synthesis of (±)-eremophilenolide, (±)-eremophiledinone, and (±)-deoxyeremopetasidione

A new and efficient route to the family of eremophilanes is reported. Key steps are the highly stereocontrolled Diels-Alder reaction and aldol condensation to furnish a cis-decalin system with the desired stereochemistry present in the eremophilane family of natural products. This approach is general and was utilized for the synthesis of (±)-eremophilenolide, (±)-eremophiledinone, and (±)-deoxyeremopetasidione.     

A new method of synthesising (±)-thalictroidine and (±)-hygrine

A new route to synthesise (±)-thalictroidine and (±)-hygrine by tandem S_N2-Micheal reaction is described.     

(±)-Mesembrine的全合成

以3-乙氧基-2-环己烯酮羰基邻位芳基化反应与Tsuji-Trost反应的串联反应作为关键步骤来构筑季碳中心, 完成了番杏科生物碱Mesembrine的全合成. 从商品化原料出发经6步反应以17.8%的总收率合成得到(±)-Mesembrine.     

Formal synthesis of (±)-brazilin and total synthesis of (±)-brazilane

A convergent synthesis towards (±)-brazilin and (±)-brazilane has been reported from 3,4-dimethoxy benzaldehyde in <15 reaction steps. Palladium(II)-catalysed intramolecular Friedel–Crafts cyclisation and Lewis acid supported intermolecular Friedel–Crafts alkylation reactions have been demonstrated. A tetracyclic substituted indane common key intermediate is employed to furnish the desired two molecules in good to excellent yield. Pd(OH)₂ has played a crucial role in the total synthesis of (±)-brazilane.     

Protecting group free syntheses of (±)-columbianetin and (±)-angelmarin

A five-step and protecting group free synthesis of (±)-columbianetin from cyclohexane-1,3-dione is reported. The former compound was converted into its p-hydroxycinnamate derivative, (±)-angelmarin, using Coster’s esterification procedure. Efforts to modify the synthesis so as to prepare angelmarin and columbianetin in an enantioselective manner are described.     

Total synthesis of (±)-pentenomycin

A concise stereoselective route to (±)-pentenomycin 1 in 33% overall yield starting from the readily accessible Diels-Alder adduct 4 is reported. The key reaction involves decarbonylation of β-methoxy-α,β-unsaturated aldehyde 8 obtained from β-hydroxy-dimethylketal 6.     

One-pot, large-scale synthesis of Nickel(II) complexes derived from 2-[N-(alpha-picolyl)amino]benzophenone (PABP) and alpha- or beta-amino acids

A one-pot, large-scale procedure for preparing the Belokon-Soloshonok nucleophilic glycine equivalent 2-[N-(alpha-picolyl)amino]benzophenone (PABP) derived Ni(II) complex [GlyNi(II)PABP] is described. It has been accomplished by using isobutyl chloroformate to form PABP and then NaH/KOH as mixed bases to afford the corresponding complexes in a one-pot manner (up to an overall yield of 98%). The potential of this method for preparation of beta-amino acids derivatives, such as beta-AlaNi(II)PABP and beta-PheNi(II)PABP, has been demonstrated. The structure of beta-AlaNi(II)PABP is characterized by single-crystal X-ray diffraction.     

Concise total syntheses of (±)isopaucifloral F, (±)quadrangularin A, and (±)pallidol

Concise total syntheses of (±)isopaucifloral F, (±)quadrangularin A, and (±)pallidol, starting from commercially available 3,5-dimethoxybenzoic acid, have been achieved by a sequential process. The overall synthetic strategy involves Nazarov cyclization, Ramberg-Backlund olefination, and Friedel-Crafts alkylation.     

The total synthesis of (±)-arisugacin A

A 20-step total synthesis of (±)-arisugacin A with an overall yield of 2.1% is described here in detail. This synthesis features a formal [3+3] cycloaddition reaction of α,β-unsaturated iminium salts with 6-aryl-4-hydroxy-2-pyrones through a highly stereoselective 6π-electron electrocyclic ring-closure of 1-oxatriene. A strategic dihydroxylation-deoxygenation protocol leading to the desired angular C12a-OH was developed to serve as a critical step in leading to the final total syntheses of arisugacin A. This synthetic endeavor also led to an interesting and unexpected retro-aldol-aldol sequence in the AB-ring.