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The preparation of two new propellanes containing the oxazino-oxazine moiety is described. The structure of 2,7-dioxa-5,1O-diaza[4.4.4] propellane was determined by X-ray crystallographic analysisThe formation of tricyclic compounds joined by a carboncarbon single bond has been of great synthetic interest. Propellanes w i t h three or four membered ring systems can be synthesized by the reaction of indan-Zone with carbenes,l photochemical m g e m e n t of b,yunsaturated cyclic ketones2 or by photochemical cycloaddition of 1,2-dichloro-ethylene to bicyclo[3.3.0]oct-5-en-2-one.3 In the case of propellanes containing five-or six-membered rings, various synthetic methods have been described.4 These propellanes show interesting stereoelectronic effects, specially the 2,5,7,10,11,14-hexaoxa-[4.4.4]pr0pellane.~ During our study of condensation reactions between aminoalcohols and adicarbonyl compounds, different structure types including mono-, bi-and tricyclic 1294 ORTfZ ET AL. ring systems have been obtained.6 Herein we describe the formation of the new heternpropellanes 1 and 2 by condensation of erhanolamine or o-aminophenol with 1.2-cyclohexanedione (scheme 1). 11 11 8 18 19 14 14 1 2 Scheme 1The I.eaction between the aminoalcohols and 1.2-cyclohexanedione was carried out under the following conditions: ethanolamine (17.8 mmol) was added dropwise to a solution of cyclohexanedione (8.92 mmol) in ethyl acetate (60 ml) and the mixture was refluxed for 7h. The solid formed was ffltered and washed w i t h a 1:l mixture of chlorofodhexane to give 2.7-dioxa-5. 10-diaza[4.4.4]propellane7 (1) in 73% yield. In the case of 2 a solution of 1.2-cyclohexanedione (8.9 mmol) and 0-aminophenol(l7.8 mmol) in ethanol (30 ml) was refluxed for 2h. The solid formed was filtered and washed with ethyl acetate to give (3,4,8,9)-dibenzo-2,7-dioxa-5,10-diaza[4.4.4]propellane~ (2) in 60% yield. 3 4 Fig. 1 Downloaded by [Tulane University] at 02:45 28 September 2014 HETEROPROPELLANES 1295 ci2 N10 Fig. 2 Molecular structure of compound 1The molecular ion at m/z =198 from mass spectromeuy could be amibuted to the structure types 1,3 or 4. Smcture 3 can be excluded based on the 13C NMR data which show only one signal at S = 84.0 ppm for the C-1 and C-6 carbons.However, spectroscopic methods do not allow an easy distinction between 1 and 4. Therefore the propellane type struchlre of compound 4 was determined by Xray crystallographic andysisg. The molecule is located on a special position in the crystal lattice showing C2 symmetry and consists of three fused six-membered rings in a chair-like conformation as shown in Fig. 2 . Additionally a stabilizing anomeric effect from the nitrogen atoms can be observed. Due to the presence of stereoelectrunic effects, the Cl-N10 bond length (1.431(4)& is significantly shorter than C4-NlO (1.463(4)h. Furthermore, the 02-Cl bond length (1.455(3)& is longer than 0 2 x 3 (1.432(4) A). From these observations it may be concluded that the predominant factor in the formation of compound 1 over 4 is the presence of ...

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