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Notes: Reactions of Aziridino-nitrenes: Synthesis of Polycyclic Bisaziridines and 1,2-Bisaziridino-diazenesVorgetragen in der Versammlung der Schweizerischen Chemischen Gesellschaft in Bern am 7.Oktober 1977.7-Amino-7-azabicyclo[4.1.0]-3-heptene (11b), cis-9-amino-9-azabicyclo[6.1.0]-nonane (12b), cis-9-amino-9-azabicyclo[6.1.0]-(4Z)-nonene (13b), as well as exo- and endo-3-amino-3-azatricyclo[3.2.1.02,4]-6-octene (14b and 15b) were synthesized by addition of oxidatively generated phthalimido-nitrene (6) to 1,4-hexadiene, (Z)-cyclooctene, (1Z,5Z)-cyclooctadiene, and bicyclo[2.2.1]heptadiene, respectively, followed by hydrazinolysis of the corresponding N-phthalimido-aziridines 11a-15a.Lead tetraacetate oxidation of the two unsaturated N-amino-aziridines 11b and 15b at -70° yielded diazapolycyclic structures by intramolecular addition of the intermediate aziridino-nitrenes 11c and 15c to the δ, ε-situated C, C-double bond; the products obtained in good yields were 1,5-diazatetracyclo [3.3.0.02,8. O4,6]-octane (16) and 3,7-diazapentacyclo [3.3.1.02,4.03,7.06.8] nonane (17), respectively Oxydation of the unsaturated N-amino-aziridine 13b under the same conditions did not cause intramolecular addition of the nitrene 13c to the ε, ζ-situated C, C-double bond; instead 1,2-bis (cis-9-azabicyclo [6.1.0]-(4Z)-nonen-9-yl)-diazene (20) was obtained in low yield and (1Z, 5Z)-cyclooctadiene as the main product. Both products can be rationalized as derived from the intermediate nitrene 13c with 13b and the olefine as the result of a fragmentation of 13c under extrusion of N2. As. expected, oxidation of the saturated N-amino-aziridine 12b led to the 1,2-bisaziridino-diazene 21 and (Z)-cyclooctene in a ratio of 4:6. Surprisingly, oxidation of 7-amino-7-azabicyclo [4.1.0]-heptane (10b) produced only fragmentation of the corresponding nitrene 10c to cyclohexene. Finally, oxidation of the exo-N-amino-aziridine 14b yielded a complex not yet resolved product mixture in low overall yield. Attempts to add the oxidatively generated aziridino-nitrene 12c to cyclohexene, methyl acrylate, and dimethylsulfoxide were without success.Heating the 1,2-bisaziridino-diazenes 20 and 21 at their respective m.p. temperatures caused thermal fragmentation to occur with evolution of nitrogen. The bisaziridines 26 and 28 as well as the aziridines 27 and 29, respectively, were isolated. These products could be the result of a radical pathway, whereas a small amount of (Z)-cyclooctene, also generated in the thermolysis of 21, might be formed by a competing cheletropic pathway.The 1H-NMR-spectra of the derivatives of cis-9-azabicyclo[6.1.0]nonane, namely of 12a, 12b, 21, 28 and 29, showed signals for some of the aliphatic protons which were separated from the others at relatively low field (around 2.5-1.8 ppm). These signals accounted for 4 (with 12b for 2) protons in each of the cis-9-azabicyclo[6.1.0]nonane subunits, i.e. more than the 2 expected for the aziridine methine protons. The additional signals must be assigned to methylene protons (2 or even 4 of them) probably situated on the other side of the eight membered ring and deshielded by the motion-average proximity to the aziridine nitrogen atom.

Notes: Reaction of Diphenylcyclopropenone with β-Carbonyl-enolates. I. Use of Acetylacetone, Methyl Acetoacetate, 2-Ethoxycarbonyl-cyclododecanone and Dimethyl MalonateThe reaction of the sodium salts of acetylacetone (6), methyl acetoacetate (7), 2-ethoxycarbonyl-cyclododecanone (8), dimethyl malonate (19) and its methyl derivative 20 with diphenylcyclopropenone (5) in dimethylformamide at room temperature led to the unsaturated γ-lactones 14, 15, 17, 22 and 36. In the case of dimethyl malonate (19), the halfester 21, the acyl-malonic ester 24 and the indenone-malonic ester 23 were also isolated.Several intermediates and the final products were characterised by reactions and spectroscopically. A general mechanism is discussed for the addition of cyclo-propenones (1) to the enolate salts of β-dicarbonyl compounds 4 involving the bicyclic lactone-enolates 18 and 32 as intermediates. The products formed via 18 and 32 are considered to be the result of an attack of one of the oxygen atoms of the β-carbonyl-enolate anion (4), the product 24, on the other hand, of the attack of the α-carbon atom of 4; in both cases the attack is on the carbonyl C-atom of 5.

Notes: Conversion of the Diastereoisomeric 12-and 6-membered 1-Acetyl-2-methyl-1-cycloalkanols to 1-Ethynyl-2-methyl-1-cycloalkenesThis paper is concerned primarily with a derivation of the E-configuration of 1-ethynyl-2-methyl-1-cyclododecene (10), which plays a role in mechanistic considerations on a method for ring expansion by 3 carbon atoms described in apreceding paper [1]. The derivation is based on an argument using the results of the dehydration of trans-1-acetyl-1-2-methyl-1-cyclododecanol (4) to 10 with phosphorus oxychloride and pyridine. That this dehydration is stereospecific can be concluded from its regiospecificity since the cis-hydroxyketone 3 dehydrates mainly to 1-ethynyl-12-methyl-1-cyclododecene (mixture of stereoisomers 11 and 12). An x-ray analysis shows the indicated configurations of the two hydroxyketones 3 and 4.The direction (anti) of the stereospecificity of the double bond introduction during the 4→10 conversion is deduced from the similarity of the behaviour of the two stereoisomeric 1-acetyl-2-methyl-1-cyclohexanols 8 and 9 under the same conditions and from mechanistic considerations, which make it likeley that the anti-elimination behaviour observed in the 6-membered system has not changed over to a syn-elimination behaviour in the 12-membered system. The configurations of the two 6-membered hydroxyketones 8 and 9 correspond to those of the precursor1-ethynyl-2-methyl-1-cyclohexanols 6 and 7, which were clarified with the help of 13C-NMR.-spectral coupling observations.It is of interest that the hydroxyketones 3, 4, 8 and 9 react with phosphorus oxychloride and pyridine so as to introduce both a double and a triple bond. It is probable that the double bond is introduced first, inasmuch as the triple bond is not introduced in the absence of activation of the hydroxyl group, as for instance in acetylcyclohexane. This can be used as an argument that the conversion of the acetyl to an ethynyl group in 3, 4, 8 and 9 does not affect the stereospecificity of the dehydration which introduces the ring double bond.1-Acetyl-2-methyl-1-cyclododecene (24), a previously isolated compound with pleasant odor, was synthesized by hydration of 10. This furnishes an argument for the E-configuration of 24.