Substituted 9-Oxabicyclo[4.2.1]- and 9-Oxabicyclo[3.3.1]nonanes (Part II)

The preparation, isolation, structure determination, and some reactions of the two stereoisomers of 2-iodo-9-oxabicyclo[4.2.1]nonane ( 9 and 10 ) and of 2-iodo-9-oxabicyclo[3.3.1]-nonane ( 11 and 12 ), respectively, are described. Iodine cleavage of the [4.2.1]-iodomercuri compound 3 yielded the iodides 9, 10 , and 11 , and iododemercuration of the [3.3.1]-iodomercuri compound 6 afforded the iodo compounds 9, 11 , and 12 , respectively. Direct treatment of 4-cycloocten-1-ol ( 1 ) with iodine in chloroform resulted in the exclusive formation of the two endo-iodides 9 and 11 . Raney nickel treatment as well as lithium aluminium hydride reduction of each índividual iodo compound 9, 10, 11 , and 12 gave the corresponding unsubstituted 9-oxabicyclononane ( 4 or 8 , respectively) with the unaltered skeleton. No rearrangement products could be observed. An oxonium ion is involved as an intermediate in the reaction of the endo-iodides 9 and 11 with silver acetate leading to an identical mixture of the two acetates 15 and 16 as well as in the isomerization of 9 to 11 .     

Substituierte 9-Oxabicyclo[4.2.1]- und 9-Oxabicyclo[3.3.1]nonane III. neue ergiebige synthese von 2, 7-dioxatwistan und endo-2-hydroxy-9-oxabicyclo[3.3.1]nonen-(6)

Iodine cleavage of the [3.3.1]-iodomercuri compound 4 , easily prepared from cis, cis-cyclooctadiene-(1,5) by oxymercuration of the monoepoxide 1 (→ 3 ) followed by treatment with potassium iodide, leads to three isomeric iodides 6, 7 , and 8 , the [3.3.1]-exo-iodo isomer 8 being the predominant product. Intramolecular substitution in 8 opens an attractive new route to unsubstituted 2,7-dioxatwistane ( 19 ) [2], whereas dehydrohalogenation of 7 and 8 yields the unsaturated alcohol 17 [2], a suitable starting material for the preparation of substituted 2,7-dioxatwistanes [2], 2,7-dioxaisotwistanes ( e ) [2], and 2,8-dioxa-homotwistbrendanes ( f ).     

Substituierte 9-Oxabicyclo[4.2.1]- und 9-Oxabicyclo[3.3.1]nonane IV. endo,endo-2,5-Dihydroxy-9-oxabicyclo[4.2.1]nonan,endo, endo-, endo,exo- und exo,exo-2,6-Dihydroxy sowie endo,exo-2,7-Dihydroxy-9-oxabicyclo[3.3.1]nonan; Darstellung und Umwandlungsprodukte

The synthesis of the following compounds and reaction products thereof are described: endo, endo-2,5-dihydroxy-9-oxabicyclo[4.2.1]nonane ( 3–5 ), epimeric 2,6-dihydroxy-9-oxabicyclo[3.3.1]nonanes (endo, endo: 6–8 , exo, exo: 29–32 , and endo, exo: 43–45 ), and endo, exo 2,7-dihydroxy-9-oxabicyclo[3.3.1]nonane ( 46–50 ).     

Organosilicon chalcogenides with trisilane units - bicyclo[3.3.1]nonanes, bicyclo[3.2.2]nonanes and spiro[4.4]nonanes

Treatment of 1,2,3-trichloropentamethyltrisilane (1) with H₂S/NEt₃ results in the formation of a mixture of two isomers of (Me₅Si₃)₂S₃ with a bicyclo[3.3.1]nonane (2a) and a bicyclo[3.2.2]nonane (2b) skeleton, while the reaction of 1 with Li₂Se yields one product only, (Me₅Si₃)₂Se₃ (3a), with a bicyclo[3.3.1]nonane structure. Besides ¹H, ¹³C, ²⁹Si and ⁷⁷Se NMR spectroscopy 3a has also been characterized by a crystal structure analysis.Compounds Si(SiMe₂EMR₂E)₂ (5a-h: MR₂: SiMe₂ (5a, c, d), SiPh₂ (5b), GeMe₂ (5e, f), SnMe₂ (5g, h); E=S (5a, b, e, g), Se (5c, f, h), Te (5d)) with a spiro[4.4]nonane skeleton have been obtained in mixture with varying amounts of the corresponding six-membered rings (R₂ME)₃ by reactions of mixtures of 1,2,2,3-tetrachlorotetramethyltrisilane (4) and diorganodichlorosilanes, Me₂GeCl₂ or Me₂SnCl₂, with H₂S/NEt₃, Li₂Se or Li₂Te and have been characterized in situ by multinuclear NMR spectroscopy (¹H, ¹³C, ²⁹Si, ¹¹⁹Sn, ⁷⁷Se, ¹²⁵Te) and GC-MS.     

3,7-disubstituted bicyclo [3.3.1] nonanes—II : Synthesis and conformation of some 3,7-disubstituted 9-oxobicyclo [3.3.1] nonanes

Condensation of pyrrolidine enamines of 4-alkylcyclohexanones with methyl α-(bromomethyl)acrylate affords methyl 7β- and 7α-alkyl-9-oxobicyclo [3.3.1] nonane-3α-carboxylates in a ratio of 3:2. The mechanism of the annelation reaction is discussed. The conformations of the reaction products and their epimers have been studied by means of PMR spectroscopy.     

The electron impact induced fragmentations of some 7-alkyl-3-oxabicyclo[3.3.1]nonanes

The mass spectra of a series of 7-alkyl substituted 3-oxabicyclo[3.3.1]nonanes are recorded. The fragmentation has been studied by the use of the metastable DADI and defocussing techniques. The character of the alkyl group is found to influence the fragmentation pattern. Stereoselective fragmentations for the 7-t-butyl derivatives are observed. In the endo-isomer, in contrast to the exo-isomer, a transannular hydrogen transfer plays a role.     

Functionalized Cycloheptanes from Bicyclo[4.2.1]nonanes

Several oxidative, reductive and C,C-cleavage reactions were performed starting from the three bicyclo[4.2.1]nona-3,7-diene-2-one derivatives 1, 5 and 18 . The oxidations were selective and led to the diols 2,8 and 9 , and the epoxides 6,9 , and 20 . The reductions were selective only in the case of 20 21 ; otherwise they led to mixtures of the alcohols 10 and 11 , and of the dienes 14 and 15 . The periodate ring cleavages afforded the functionalized cycloheptane derivatives 3, 12, 13 and 16 . Configurational assignments were made on the basis of detailed ¹H-NMR and X-ray analysis of 20 .     

Facile and convenient synthesis of B-amino-9-borabicyclo[3.3.1]nonanes. Aminoboration of lsocyanates

The reaction of 9-borabicyclo[3.3.1]nonane (9-BBN) with aliphatic and aromatic primary and secondary amines in tetrahydrofuran (THF) at 65°C proceeds rapidly and quantitatively with evolution of hydrogen and the formation of the corresponding B-amino-9-borabicyclo[3.3.1] nonane (B-amino-9-BBN). Simple evaporation of THF from the reaction mixture gives the B-amino-9-BBN derivatives in high yield and purity. These B-amino-9-BBN derivatives are reactive towards alkyl and aryl isocyanates. Consequently, the aminoboration of various isocyanates has been studied using B-phenylamino-9-BBN. Thus, two equivalents of isocyanates react with one equivalent of B-phenylamino-9-BBN to afford, following the hydrolysis of the intermediate with ethanolamine, N, N'-disubstituted-N -(phenylamido)-ureas in excellent yields. A plausible mechanism for this aminoboration reaction of isocyanates is also presented.     

The mass-spectral fragmentation of bicyclo[3.3.1]nonanes

The mass spectra of twelve bicyclo[3.3.1]nonanes have been recorded. The high number of metastables observed, exact mass measurements of the ions and low ionising voltage spectra, permitted the rationalisation of most of the fragmentation pathways. The 1-phenyl substituent triggers the major fragmentation in the hydrocarbon, whereas it has minor influence in the oxygenated compounds. Significant differences in the abundance of [M ? H₂O]⁺ ions for stereoisomeric alcohols of this series have been observed.     

A homo Diels-Alder approach to bicyclo[4.2.1]nonanes

[reaction: see text] A new, high-yielding route to functionalized bicyclo[4.2.1]nonanes has been achieved utilizing homo Diels-Alder chemistry with subsequent Zeise's dimer-catalyzed opening of the cycloadduct.     

One-pot conversion of carboxylic acids to aldehydes through treatment of acyloxy-9-borabicyclo[3.3.1]nonanes with lithium 9-boratabicyclo[3.3.1]nonane

Carboxylic acids are readily reduced to the corresponding aldehydes in high yields by treatment of acyloxy-9-borabicyclo[3.3.1]nonanes with lithium 9-boratabicyclo[3.3.1]nonane (Li 9-BBNH) at room temperature.     

Synthesis and Transformations of 1,3,5,7-Tetraazabicyclo[3.3.1]nonanes

Published data on the synthesis of 3,5-disubstituted 1,3,5,7-tetraazabicyclo[3.3.1]nonanes and their transformations into 1,3,5,7-tetraazacyclooctanes and 1,3,5-triazacyclohexanes are discussed.     

Complexation properties of 3,7-diazabicyclo[3.3.1]nonanes

The electrochemical behavior of some 3,7-diazabicyclo[3.3.1]nonanes and their complexes with copper(II) chloride was investigated. The composition and stability of complexes are discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 456–458, March, 1995.     

The question of the reversibility in the aminomercuration of olefins. Synthesis of N-aryl-9-azabicyclo[4.2.1]and [3.3.1] nonanes by aminomercuration of cis-cis- 1.5-cyclooctadiene

The aminomercuration of olefins is found to be a reversible or irreversible process depending on the nature of the mercury(II) salt employed. This is in clear contrast with the mechanism of oxymercuration reactions. A selective synthesis of the title compounds is described by kinetically or thermodinamically controlled aminomercuration of cis-cis-1,5-cycloctadiene.