A short and efficient asymmetric synthesis of komaroviquinone

An asymmetric total synthesis of komaroviquinone (1), which is a natural product isolated from Dracocephalum komarovi and shows novel potent trypanocidal activity, was achieved in five steps from the known starting materials. The synthetic route is shorter and more efficient than the reported methods and also useful for the scale-up synthesis.     

A short and efficient synthesis of renealtins A and B

The total syntheses of the first examples of diarylheptanoid natural products, renealtins A (1) and B (2), isolated from Renealmia exaltata are described, utilizing a δ-lactone intermediate 9. The key reactions involved are asymmetric dihydroxylation and oxy-Michael addition.     

A short and efficient synthesis of crocetin-dimethylester and crocetindial

In this paper we describe an efficient six-step synthesis of crocetin-dimethylester that could be further reduced to a "four-step" synthesis through the use of in situ procedures. The simplicity of the whole process, the ready availability of starting materials, and the high overall yield render this strategy a very attractive synthesis of this very important compound, which is the key intermediate for the synthesis of several carotenoids and other polyene natural products.     

A short and efficient stereoselective synthesis of dihydrosphingosine triacetate

A highly enantiocontrolled synthesis of -(+)-erythro-dihydrosphingosine (sphinganine) triacetate is described using the Sharpless asymmetric dihydroxylation and the regiospecific nucleophilic opening of a cyclic sulfite as key steps.     

A short and efficient synthesis of honokiol via Claisen rearrangement

A concise and efficient total synthesis of honokiol, a biphenyl-type neolignan is accomplished in six steps using readily available and cost-effective reagents. The synthetic route involves mainly the Grignard reaction, iodine mediated aromatization, and Claisen rearrangement as key steps. A predominant formation of honokiol (1a) was observed in the Claisen rearrangement under microwave irradiation whereas the isohonokiol (1b) was formed as a major product under conventional conditions.     

A novel, short and efficient synthesis of divinyl ethers

An efficient one-step synthesis of divinyl ethers from aldehydes and ketones using Wittig olefination is described.     

A novel short and efficient asymmetric synthesis of statine analogues

The statine analogues 1a–c have been obtained in high optical purity via addition of the chiral acetate enolate 4 to the α-aminoaldehydes 5a–c, followed by transesterification.     

A short efficient synthesis of 4-amino-2,3-dihydrobenzofuran

A new, practical synthesis of 4-amino-2,3-dihydrobenzofuran is described. Chlorination and a Sandmeyer reaction of the title compound are also reported.     

A short and highly efficient synthesis of L-ristosamine and L-epi-daunosamine glycosides

A highly efficient synthesis of L-ristosamine and L-epi-daunosamine glycosides via BF(3)·OEt(2) promoted tandem hydroamination/glycosylation of 3,4-di-O-acetyl-6-deoxy-L-glucal and L-galactal has been developed. The new method proceeds in a completely stereocontrolled manner within a short reaction time. Preparation of a library of L-ristosamine and L-epi-daunosamine glycosides with potential biochemical applications, by varying each component, exemplified the generality of the reaction.     

A short and efficient synthesis of (+)-disparlure and its enantiomer

A short and highly efficient approach was applied for the total synthesis of the gypsy moth sex pheromone (+)-disparlure and its enantiomer from isopropylidene D- and L-erythrose, using a common strategy.     

A short and efficient general synthesis of luotonin A, B and E

Highly convergent synthesis of three luotonins (A, B, and E) has been achieved from readily available starting materials. The key step in the synthesis is formation of quinazolinone skeleton by the condensation of 3-(1,3-dioxolan-2-yl-quinoline-2-carbaldehyde and anthranilamide.     

A short and efficient synthesis of (R)-(−)-sporochnol A

A short and efficient synthesis of (R)-(−)-sporochnol A in five steps and 9% overall yield has been developed. The sequence uses as starting material the easily available enantiopure monoketal derived from 1,4-cyclohexanedione and (R,R)-hydrobenzoin that serves as a chiral auxiliary.     

A short and efficient stereoselective synthesis of the polyhydroxylated macrolactone (+)-aspicillin

[structures: see text] A short and efficient synthesis of the polyhydroxylated macrolactone (+)-aspicilin 1 using a stereoselective lithium perchlorate mediated addition of allyltributyltin to the equatorially disposed carboxaldehyde of 3 (derived from (R',R',R,S) butane diacetal protected butane tetrol 2) as the key step is described. Terminal group manipulation and Masamune-Roush olefination using phosphonate ester 4 followed by macrocyclization via ring closing metathesis afforded the natural product after partial hydrogenation and global deprotection.     

A short efficient synthesis of 19-norandrost-4-ene-3,17-dione

A three-step conversion of 3aα-H-4α-(3′-propionic acid)-7aβ-methylhexahydro-1,5-indanedione into 19-norandrost-4-ene- 3,17-dione is described.     

A short and efficient synthesis of the tRNA nucleosides PreQ0 and archaeosine

Modified nucleosides in tRNAs play an important role in the translational process. They fine tune the codon-anticodon interactions and they influence the folding and stabilisation of the tRNA structure. Herein, we present a novel synthetic route to the highly modified nucleosides PreQ(0) and archaeosine. The synthesis involves coupling of a protected 7-cyano-7-deazaguanosine nucleobase with a TBDMS and isopropylidene protected chloro-ribose unit yielding the PreQ(0) nucleoside after deprotection. This PreQ(0) nucleoside is then used as the starting material for the synthesis of archaeosine providing the first total synthetic access to this hypermodified RNA nucleoside.     

Synthesis of grisan

Grisan (Spiro[benzofuran-2(3H)1'-cyclohexane], 2) has been synthesized for the first time starting from cis-2-(2-hydroxybenzyl)-cyclohexanol (7).