Sulfur-silicon rings

Paritosh, D. R. et al Chem. Abs., 1994, 121, 35869j U.S. Pat. Appl. 42,229 Paritosh, D. R. etal., Phosphorus, Sulfur, Silicon Relat. Elem., 1994, 90(1-4), 175 This and several other compounds with fewer nitro groups and partial replacement of the spiro rings by halogen are patented as explosives. 

Sulfur-nitrogen rings and cages are discussed in Sulfur-Nitrogen Compounds. There are several boron-sulfur and silicon- sulfur rings and examples are given in Figure 51. 

For reviews on related topics, see a) Bourissou D, Bertrand G (1999) Acc Chem Res 32 561 b) Canac Y, Bourissou D, Gornitzka H, Schoeller WW, Baceiredo A, Bertrand G (1999) Phosphorus Sulfur Silicon 144-146 37 c) Etemad-Moghadam E, Koenig M (1996) Three-membered rings with two heteroatoms including phosphorus to bismuth. In Katritzky AR, Rees CW, Scriven EFV (eds) Comprehensive heterocyclic chemistry II. Pergamon, Oxford, vol 1 a, p 469... 

While nitrogen, sulfur, silicon, and phosphorus are important heteroatoms, we will look briefly only at nitrogen and sulfur compounds. In general, when the heteroatom is incorporated into an aromatic ring, strong molecular ions are seen. Table 10.4 should be reviewed to remind yourself of the isotope ratios for these heteroatoms to help in interpreting spectra. 

Riegel B, Pfitzner A, Heckmann G, Pluck E, Binder H (1994) Phosphorus-boron and phosphorus-silicon ring systems functionalization of phosphorus ring systems. Phosphorus Sulfur Silicon 93-94 173-176... 

The [5,5]-fused bicyclic ring system with one fusion nitrogen atom and three additional heteroatoms in a 2 1 distribution over both ffve-membered rings (2N1) is the origin of a great number of structures. The additional heteroatoms are mainly nitrogen, oxygen, or sulfur, and less commonly phosphorus or silicon atoms. 

Electrophilic attack at ring silicon, sulfur, selenium, and phosphorus Nucleophilic attack at ring silicon Nucleophilic attack at ring boron... 

Heterocyclic Sulfur Compounds with Two or More Rings Hexachlorobenzene under Ring-Substituted Aromatics Hexachlorobutadiene under Unsaturated Alkyl Halides Hexachlorocyclohexane Lindane under Saturated Alkyl Halides Hexachlorocyclopentadiene under Unsaturated Alkyl Halides Hexachloroethane under Saturated Alkyl Halides Hexadecane under Alkanes and Cyclic Alkanes Hexafluoroethane under Saturated Alkyl Halides Hexamethyldisihzane under Silicon Compounds—Other Significant Hexanes under Alkanes and Cyclic Alkanes Hexylamine under Primary Aliphatic Amines and Diamines... 

The chemistry of silacyclopentanes resembles closely that of acyclic alkylsilanes. Strong bases are needed to cleave the silicon-carbon bond, while electrophilic attack occurs readily with halogens and strong acids, e.g. sulfuric. In addition, aluminum chloride will induce polymerization of silacyclopentanes unless one of the groups on silicon is carbofunctional (Scheme 154) (67MI12000). If this is chloromethyl, then ring expansion occurs (Scheme 155). 

Germylene insertion into germacyclobutanes to give 1,2-digermacyclopentanes has already been described (Scheme 88). However, the tetraethyl derivative (95) is better made via the mercury derivative (Scheme 162). Like its silicon counterpart, (95) is slowly oxidized at room temperature, and inserts sulfur, selenium and bromine in the Ge—Ge bond. While (95) is less stable than the 1,2-digermacyclohexane, dichlorocarbene inserts into the /3-C—H bond of both rings, and not the Ge—C bond (Scheme 163) (69JOM(16)227). 

The synthesis of heterocycles containing both silicon and sulfur in the ring from linear thiols have recently been described by Kirpichenko and coworkers190 (Scheme 66). 

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