Synthesis of Tetraacetal Pentaoxa-Cages and Convex Oxa-Cages by Ozonolysis of 7-Oxabicyclo[2.2.1]heptenes

Lin, Chung Chih; Wu, Hsien‐Jen

doi:10.1055/s-1996-4291

Cited by 29 publications

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“…The utility of ozonolysis in organic synthesis usually centers on the chemical transformation of an alkene bond to carbonyl groups or to an α-alkoxy hydroperoxide if an alcohol is present . Recently, we utilized the ozonolysis reaction for the synthesis of a series of oxa cage compounds, such as diacetal trioxa cages, triacetal trioxa cages, tetraacetal tetraoxa cages, and tetraacetal pentaoxa cages . Later on, we investigated the chemical nature of the acetal group of tetraoxa cages and discovered a hydride rearrangement and a one-pot conversion from oxa cages to aza cages .…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Pentaoxa[5]peristylanes

1999

J. Org. Chem.

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The synthesis of alkyl-substituted pentaoxa[5]peristylanes has been accomplished by ozonolysis of 2,3-bis-endo-7-anti-triacylnorbornenes 6a-d and by direct chemical transformation of the tetraacetal tetraoxa cages 11 and 12. Various reaction conditions have been used to optimize the overall yield for the synthesis of methyl group substituted pentaoxa[5]peristylane 7d. Ozonolysis of 6d in CDCl(3) at -78 degrees C without reduction was performed to study the ozonolysis chemistry of the triacylnorbornenes 6a-d. The synthesis of the parent (unsubstituted) compound 25 of pentaoxa[5]peristylane has been accomplished by a three-step efficient sequence with a maximum 45% overall yield via ozonolysis of the dihemiacetal 24. The structure of pentaoxa[5]peristylanes was proven by X-ray analysis of the parent compound 25. The syntheses of the triacetal tetraoxa cage 26, a new type of oxa cage, and a new entry for the synthesis of the parent compound 33 of tetraacetal tetraoxa cages were also demonstrated.

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Section: Introductionmentioning

confidence: 99%

Synthesis of Pentaoxa[5]peristylanes

1999

J. Org. Chem.

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“…of C(3)-O(4)-C(5) of the tetraoxa-cages 1. While the other C-O-C bond angles of these tetraoxacages are in between 111°-108 °, the C(3)-O(4)-C (5) bond angle is 117.5 °, remarkably larger than the ordinary bond angles with sp3-hybridized atoms. 4a The stability and size of the ring may also be an important factor for the high regioselectivity.…”

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confidence: 85%

A novel one-pot conversion of tetraacetal tetraoxa-cages to aza-cages mediated by iodotrimethylsilane in acetonitrile

Chern

1997

Tetrahedron Letters

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Treatment of the tetraacetal tetraoxa-cages la-f with excess of iodotrimethylsilane in acetonitrile at 25 °C gave the novel tetraacetal trioxamonoaza-cages 2a-f in 75-80% yields respectively, a novel one-pot conversion of oxa-cages to aza-cages. © 1997 Elsevier Science Ltd.The reaction chemistry of acetals has been greatly expanded by the use of Lewis acidic promoters particularly in conjunction with silicon-containing nucleophlies) '2 Usually, acyclic and monocyclic acetals, especially the acetal groups in monosaccharide derivatives, are the objects for study. 3 Recently, we accomplished the synthesis of novel oxa-cage compounds, such as tetraacetal tetraoxa-cages, 4 tetraacetal pentaoxa-cages, ~ triacetal trioxa-cages, ~ diacetal trioxa-cages, 7 and pentaacetal pentaoxa-cages (the pentaoxa[5]-peristylanes), s All these oxacages have acetal and ketal groups on the molecule. As part of a program that involves the synthesis, chemistry, and applications of new heterocyclic cages, we report here a novel one-step conversion of oxa-cages to aza-cages mediated by M%SiI, leading to formation of novel tetraacetal trioxamonoaza-cages. To our knowledge, a one-pot conversion of acetal group to monoazaacetal group mediated by Me3SiI has not yet been reported. ~,2Reaction of the tetraacetal tetraoxa-cages la-lf with three equivalents or more of iodotrimethylsilane in acetonitrile at 25 °C for 4 h gave the novel aza-cages 2a-2f in 80-85% yields (Scheme 1). This novel conversion takes place regioselectively on the C(3)-O(4) or 0(4)-C(5) bond. No detectable amount of the other regioisomers 3, 4, or 5 was obtained. We attribute the highly regioselective oxygen-nitrogen conversion reaction to the unusually large bond angle

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“…This class of heterocyclic cage compounds is synthesized by intramolecular alkene−oxirane (2σ−2π) photocycloaddition, by transannular cyclization of suitable compounds, by tandem cyclization, by dehydration of diols having the proper stereochemistry, by base-promoted rearrangement, and by intamolecular etherification of an alkene bond with organoselenium reagents . Recently, we utilized ozonolysis reaction for the synthesis of a series of oxa-cage compounds, such as triacetal trioxa-cages, tetraacetal tetraoxa-cages, tetraacetal pentaoxa-cages, and pentaacetal pentaoxa-cages (the pentaoxa[5]peristylanes) . Later on, we investigated the chemical nature of the acetal group of tetraoxa-cages and discovered a hydride rearrangement and an one-pot conversion from oxa-cages to aza-cages .…”

Section: Introductionmentioning

confidence: 99%

Synthesis of New Type Diacetal Trioxa-Cage Compounds via an Intramolecular Nucleophilic Addition of the Hydroxy Group to the Carbonyl Oxide Group

Chao

Lin

1998

J. Org. Chem.

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The synthesis of diacetal trioxa-cage compounds with a new type of skeleton is reported. Ozonolysis of the diols 2a − f, 21, 24, and 33 in CH2Cl2 at −78 °C followed by reduction with Me2S gave the diacetal trioxa-cages 3a − f, 22, 25, and 34 in 70−80% yields, respectively. A mechanism via an intramolecular nucleophilic addition of the hydroxy group of the diols to the carbonyl oxide group is proposed for the formation of the diacetal trioxa-cages. The effect of the number of carbon atoms at the bridge of the diols on the formation of the diacetal trioxa-cage skeleton was examined. Ozonolysis of the diols 13 and 15 under the same reaction conditions gave compounds 16 and 18, respectively. No detectable amount of the trioxa-cages 17 and 19 was obtained. For the synthesis of the diacetal trioxa-cages 28a − c and 31, which possess an alkene bond intact, ozonolysis of the diols 27a − c and 30 was performed by controlling the amount of ozone.

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Synthesis of Tetraacetal Pentaoxa-Cages and Convex Oxa-Cages by Ozonolysis of 7-Oxabicyclo[2.2.1]heptenes

Cited by 29 publications

References 0 publications

Synthesis of Pentaoxa[5]peristylanes

Synthesis of Pentaoxa[5]peristylanes

A novel one-pot conversion of tetraacetal tetraoxa-cages to aza-cages mediated by iodotrimethylsilane in acetonitrile

Synthesis of New Type Diacetal Trioxa-Cage Compounds via an Intramolecular Nucleophilic Addition of the Hydroxy Group to the Carbonyl Oxide Group

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