Conjugated heteroatom

The obvious limitation that restricts the method to planar hydrocarbons may be partially overcome by redefining modified parameters for conjugated heteroatoms in the form... 

Charge-Transfer Complexes of Ferrocenes Containing Conjugated Heteroatom Substituents... 

Reaction of carbonylcarbenes with a triple bond results in either 1,1-cycloaddition product 326 or 1,3-cycloaddition product 327. Substituted furans 327 are also accessible through photolysis, thermolysis, or catalytic rearrangement of carbonylcyclopropenes 326. However, furan formation can be imagined as a cyclization of 6ir-electron system 328, incorporating a singlet carbene or carbenoid center and a conjugated heteroatomic diene... 

Warshel A and A Lappicirella 1981. Calculations for Ground- and Excited-State Potential Surfaces for Conjugated Heteroatomic Molecules. Journal of the American Chemical Society 103.4664-4673... 

Sequential transmetaUation and protonation of 2-(2 -oxazohnyl)thien-3-yl hthium affords the mono- and bis-carbene complexes 13, 14 and 15. These complexes contain only distant (albeit conjugated) heteroatoms. ... 

Warshel, A., Lappicirella, V.A. Calculations of ground- and excited-state potential surfaces for conjugated heteroatomic molecules. J. Am. Chem. Soc. 103,4664—4673 (1981)... 

Many completely conjugated hydrocarbons can be built up from the annulenes and related structural fragments. Scheme 9.2 gives the structures, names, and stabilization energies of a variety of such hydrocarbons. Derivatives of these hydrocarbons having heteroatoms in place of one or more carbon atoms constitute another important class of organic compounds. 

Certain structural units containing heteroatoms can be substituted into conjugated systems in such a way that the system remains conjugated and isoelectronic with the original hydrocarbon. The most common examples are —CH=N— and —N—N— double... 

Tliis chapter covers nitrogen-containing fulvalenes that can be obtained by replacement of CH=CH and/or CH, for example, types 1-3 starting from compounds 1-6. Compounds in which nitrogen atoms are arranged on the periphery of the cross-conjugated system as in 15 or 16, as well as derivatives in which the central double bond contains heteroatoms as in 17, are not included. For azoniafulvalenes of type 17 and related heterocyclic betaines see (94AFIC197). 

Concerning nomenclature, fulvalene 2 and its related systems 1 and 3-6 are the parent structures of this class of heterocyclic cross-conjugated compounds. Both ring systems are numbered as shown in formula 9 (1,4,5,8-tetraazafulva-lene) beginning at the heteroatoms. Alternatively, as in the case of heptafulva-lene 10 (3,3 -diazaheptafulvalene), the numbers 1-7 and l -7 can be used.Tlie use of the name of the parent heterocycle connected by an olefinic double bond is often favored for the nomenclature of electron-rich olefines, for example, bis[3-(2,6-diisopropylphenyl)-4,5-dimethylthiazol-2-ylidene] for compound 51a (97LAR365). Similarly, azafulvalenes of type 11 and 12 can be re-... 

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