A Facile Synthesis of Dispiro-Ring Compounds Via Telluronium Ylides

The cyclopropanation reaction of α,α′-bis (substitutedbenzylidene)cycloalkanones with telluronium ylides was studied. The products were proved to be the derivative of dispiro[2, 1, 2, 2]nonane-4-one and dispiro[2, 1, 2, 3]decane-4-one.     

Synthesis of Bicyclo[2.2.1]heptan-2-ones by thermal cyclization of 3-allylcyclopentanones

Pyrolysis of 3-allylcyclopentanones affords $\text{endo}$-6-substituted bicyclo[2.2.1]heptan-2-ones.     

A Facile Synthesis of Bicyclo[4.2.0]octa-1,3,5-trien-3-ol

Bicyclo[4.2.0]octa-1,3,5-trien-3-ol (2) has been synthesized in good yield via a Baeyer-Villiger reaction of the corresponding aldehyde 5 with permonophosphoric acid.     

Regioselectivity in the Acid Cleavage of Bicyclo[4.1.0]Heptan-3-Ones

Acid-promoted cyclopropane cleavage reactions have been employed with great success for the generation of angular methyl groups.² Sims has shown that the regioselectivity of such reactions may be influenced by acid strength.^2d We now report a case in which steric factors appear to direct the cleavage pathway.     

Rh(III)-Catalyzed Annulative Coupling of Sulfoxonium Ylides with Allyl Acetates: Generation of Bicyclo[4.1.0]heptan-2-ones

A highly efficient Rhodium(III)-catalyzed annulative coupling was developed for generating bicyclo[4.1.0] heptan-2-ones from sulfoxonium ylides and allyl acetates under mild conditions. This cascade reaction is versatile to construct cyclopropanes, and the starting materials are stable and easily obtainable.     

The Non-planarity of the Bicyclo[2.2.1]hept-2-ene Double bond. Crystal Structures of Bicyclo[2.2.2]oct-2-ene,Bicyclo[2.2.1]hept-2-ene,and Bicyclo[2.1.1]hex-2-ene Systems

The crystal structures of (1R,4R,5S,8S)-9,10-dimethylidentricyclo[6.2.1.0^2,7]undec2(7)-ene-4,5-dicarboxylic anhydride ( 3 ), (1R,4R,5S,8S)11-isopropylidene-9,10-dimethylidenetricyclo[6.2.1.m^2,7]undec-2(7)-ene-4,5-dicarboxylic anhydride ( 6 ), (1R,4R,5S8S)-9,10-dimethylidenetricyclo[6.2.2.0^2,7]dodec-2(7)-ene-4,5-dicarboxylic anhydride ( 9 ), (1R4R5S8S)-TRICYCLO[6.2.2.0^2,7]dodeca-2(7), 9-diene-4,5-dicarboxylic anhydride ( 12 ) and (4R,5S)-tricyclo[6.1.1.0^2.7]dec-2(7)-ene-4,5-dicarboxylic acid ( 16 ) were established by X-ray diffraction. The alkyl substituents onto the endocyclic bicyclo[2.2.1]hept-2-ene double bond deviate from the C(1), C(2), C(3), C(4), plane by 13.5°4 in 3 and by 13.9° in 6 , leaning toward the endo-face. No such out-of-plane deformations were observed with the bicyclo[2.2.2]oct-2-ene derivatives 9 and 12 . The exocyclic s-cis-butadiene moieties in 3, 6 and 9 do not deviate significantly from planarity. The deviation from planarity of the double bond n bicyclo[2.2.1]hept-2-ene derivatives and planarity in bicyclo[2.2.2]oct-2-ene analogues is shown to be general by analysis of all known structures in the Cambridge Crystallographic Data File. The non-planarity of the bicyclo[2.2.1]hept-2-ene double bond cannot be attributed only to bond-angle deformations which would favour rehybridizatoin of the olefinic C-atoms since the double bond in the more strained bicyclo[2.1.1]hex-2-ene drivative 16 deviates from planarity by less than 4°.     

Synthesis of 4-carboxy-2-thiabicyclo [3.2.0] Heptan-6-ones via 3-carboxy-2,3-dihydrothiophenes: potential β-lactamase inhibitors

3-Carboalkoxy-2,3-dihydrothiophenes, available by Birch reduction of thiophene-3-carboxylic acid or more efficiently by deconjugation of 2,5-dihydrothiophene-3-carboxylic acid by reaction with ethyl chloroformate and triethylamine, undergo cycloaddition reactions with dichloroketene leading to 4-carboxy-7,7-dichloro-2-thiabicyclo[3.2.0]heptan-6-ones which are of interest as potential β-lactamase inhibitors.     

Synthesis of Novel Triacetal Trioxa-Cage Compounds by Ozonolysis of Bicyclo[2.2.1]Heptenes and Bicyclo[2.2.2]Octenes

Several novel triacetal trioxa-cage compounds 11a-11g, 13, 15, 17 and 19 are synthesized in a short sequence. Ozonolysis of bicyclo[2.2.1]heptenes 4a-4c, 8a-8c, 10a, 10b and 14 in dichloromethane at ?78 °C followed by reduction with dimethyl sulfide gave triacetal oxa-cages 11a-11g, 13 and 15 in moderate yields, respectively. Ozonolysis of bicyclo[2.2.2]octenes 16 and 18 under the same reaction conditions gave triacetal oxa-cages 17 and 19 in moderate yields, respectively.     

A Facile Synthesis of 2-Formylbicyclo[3.1.1]hept-2-ene

A short synthesis of 2-formylbicyclo[3.1.1]-hept-2-ene, suitable for multigram preparations, is presented.     

Synthesis of Bicyclo[n. 2. 0]alkanediols

Interest in the synthetic potential of rearrangement reactions of fused-ring cyclobutanediols^1,2 has led us to develop a general method for the synthesis of bicyclo[n.2.0] alkanediols in which the hydroxyl group are located on adjacent carbon atoms at the bridgehead and in the cyclobutane ring (e.g. 1). We report here the application of our new synthetic method to the synthesis of bicyclo [4.2.0] octane-1,8-diol (2) and bicyclo[3.2.0]-heptane-1,7-diol (3).     

A Facile Entry into Bicyclo[3.3.0] Octene System Via Anionic Oxy-Cope Rearrangement

The bicyclo[3.3.0] octene system has been synthesised from the readily available starting material 2-methyl-cyclohexane-1,3-dione, utilizing the base catalysed oxy-Cope rearrangement as a key step.     

A Remarkable Synthesis of the Bicyclo[4.2.1]Nonenedione System

Allylation of the C-2 enolate of the bicyclo[3.3.1]nonenedione 1 proceeds with an unusual acyl migration to yield the C-allyl ester 5 of the rearranged bicyclo[4.2.1]nonenedione system.     

Herstellung der reinen,bicyclischen Olefine Bicyclo[4.2.1]non-2-en,Bicyclo[4.2.1]non-3-en und Bicyclo[4.2.1]non-7-en

Synthesis of the pure, bicyclic olefines Bicyclo[4.2.1]non-2-ene, Bicyclo[4.2.1]non-3-ene and Bicyclo[4.2.1]non-7-ene The synthesis of the olefines bicyclo[4.2.1]non-2-ene ( 3 ), bicyclo[4.2.1]non-3-ene ( 4 ) and bicyclo[4.2.1]non-7-ene ( 5 ) of high ‘certified’ purity from one common precursor ( 7 ) is described.     

A New Facile Ultrasound-Assisted Magnetic Nano-[CoFe2O4]-Catalyzed One-Pot Synthesis of Pyrano[2,3-c]pyrazoles

Russian Journal of Organic Chemistry - Pyrano[2,3-c]pyrazole derivatives have been synthesized through a one-pot multicomponent condensation of various aldehydes, dialdehydes, and ketones with...     

Facile Synthesis of 2-Alkylthio-5,6,7,8-tetrahydrobenzothieno[2,3-d]pyrimidin-4(3H)-ones

Isothiocyanate 2, obtained from aza-Wittig reaction of iminophosphorane 1 with CS₂, reacted with amine to give 2-thioxo-2,3,5,6,7,8-hexahydrobenzothieno[2,3-d]pyrimidin-4(1H)-ones 4 in the presence of sodium ethoxide. S-Alkylation of 4 produced 2-alkylthio-5,6,7,8-tetrahydrobenzothieno[2,3-d]pyrimidin-4(3H)-ones 5 in good yields.     

Alkoxide-Accelerated [1,3] Sigmatropic Shift of Bicyclo[3.2.1]oct-6-en-2-ols to 8-endo-Hydroxybicyclo[3.3.0]oct-2-en-4-ones

Bicyclo[3.2.1]oct-6-en-2-ols 6 are shown to undergo [1,3] sigmatropic shift to afford 8-endo-hydroxy-bicyclo[3.3.0]oct-2-en-4-ones 8 under the influence of potassium hydride.     

An Improved Synthesis of Bicyclo[3.3.3]undecane

A shorter and significantly higher-yield procedure for the preparation of bicyclo[3.3.3]undecane (manxane) is reported.     

Bicyclo [3.3.0]Octane Derivatives for Carbaprostacyclin Synthesis

Convenient syntheses of the epimeric 3-hydroxy-2α-carb-oxybicyclo[3.3.0]octane-4α,6α-carbolactones are described which commence from the readily available cyclopentadienone dimer.