3669-59-8Relevant academic research and scientific papers
Ozonolysis of bis-endo-diacylbicyclo[2.2.1]heptenes in dichloromethane- methanol
Lin, Hui-Chang,Lin, Chu-Chung,Wu, Hsien-Jen
scheme or table, p. 7236 - 7243 (2011/10/08)
Ozonolysis of bis-endo-diacylbicyclo[2.2.1]heptenes 3a-d at -78 °C in dichloromethane-methanol gave the hydroperoxides 6a-d in 70-80% yields. Ozonolysis of bis-endo-diacetylbicyclo[2.2.2]octene 15 and bis-endo-diacetyl-7- oxabicyclo-[2.2.1]heptene 16 under the same reaction conditions gave the hydroperoxides 17 and 18, respectively. The intramolecular sequential nucleophilic addition of the carbonyl groups to the carbonyl oxide group was observed for the first time and was found to be faster than the intermolecular nucleophilic addition of a methanol molecule to the carbonyl oxide group. Ozonolysis of compound 23 in CH2Cl2-MeOH at -78 °C followed by reduction with Me2S gave compounds 24 and 25, in which the stereochemistry of the methoxyl groups was determined by X-ray analysis.
Synthesis of diacetal trioxa-cage compounds via reaction of bicyclo[2.2.1]heptenes and bicyclo[2.2.2]octenes with dimethyldioxirane
Lin, Hui-Chang,Wu, Hsien-Jen
, p. 341 - 350 (2007/10/03)
A new entry for the synthesis of diacetal trioxa-cage compounds via oxirane-induced sequential cyclization reaction of 2,3-bis-endo- diacylbicyclo[2.2.1]-5-heptenes and 2,3-bis-endo-diacylbicyclo[2.2.2]-5- octenes is reported. In the case of bicyclo[2.2.2]octenes, sequential cyclization reaction induced by iodine as electrophile failed. We have also demonstrated that dimethyldioxirane can selectively oxidize hemiacetals to give lactones with the secondary hydroxy group intact. (C) 2000 Elsevier Science Ltd.
Novel Oxa-Cage Compounds: Synthesis, Structures, and the Formation Mechanism of Tetraacetal Oxa-Cages and Convex Tetraquinane Oxa-Cages
Wu, Hsien-Jen,Lin, Chu-Chung
, p. 7558 - 7566 (2007/10/03)
Several novel tetraacetal oxa-cage compoundsa 5a-d and convex tetraquinane oxa-cage compounds 16a-d and 17b-d are synthesized from alkylfuranes in three steps.Ozonolysis of the cis-endo-1,4-diones 3a-d in dichloromethane at -78 deg C followed by reduction with dimethyl sulfide gives the oxa-cage 5a-d in high yields, respectively.The structures of these new tetraacetal oxa-cages are deduced from their spectral data and proven for the first time by X-ray analysis of the crystalline compound 5a.Ozonolysis of 3a-d in dichloromethane at -78 deg C followed by treatment with triethylamine gives the convex tetraquinane oxa-cages 16a-d and 17b-d in 85-90percent yields, respectively.The structures of these novel convex tetraquinane oxa-cages are finally proven by X-ray analysis of the crystalline compound 16a.Two reaction mechanisms via the common final ozonides are proposed for the formation of these two different types of oxa-cage compounds.The structures of the final ozonides formed by ozonolysis of the norbornene derivatives 3 are deduced to be 9 with endo stereochemistry on the basis of their spectral data and the formation of these two types of oxa-cages from the final ozonides.In reaction with the final ozonides, triethylamine is found to act as a base instead of a reducing agent, a different function from that of dimethyl sulfide.The synthesis of oxa-cages 24 and 25, which possess aromatic substituents dirctly on the skeleton, has also been accomplished.
