Lead homocycles

A combination of a ir-homocyclic or 77-heterocyclic metal moiety, a carbonylmetal fragment (CO) M, and an electron-poor boron heterocycle should lead to unsymmetrical triple-decker complexes. The first example (72) was reported by Grimes and co-workers (91), obtained from the reaction of [ (CH3—C BJIJjFeFy with [(C5H5)Co(CO)2] under UV... 

The conversion of hexose into uronic acid and pentose units of cell wall polysaccharides in higher plants may occur, not only by the sugar nucleotide oxidation pathway, which leads to UDP-uronate, but also by the myoinositol oxidation pathway. In this case, the homocyclic inositol ring is split, oxidized at C(6) and concurrently replaced by a heterocycle with an —O— bridge between C(l) and C(5), as shown by label experiments. Glucuronic acid can be generated in this way. 

The photolysis of a number of homocyclic silanes with various sized rings has been investigated in recent years much of this material appears in a recent review by Hengge and Janoschek . It is well known that the photolysis of dodecamethylcyclohexasUane leads to loss of dimethylsilylene, MeaSi , with the successive formation of the cyclopenta-and cyclotetrasUanes. This reaction constitutes a useful way to generate the silylene for various purposes. Further photolysis generally leads to complete degradation of the ring system. 

Intra-Intermolecular Polymerizations Leading to Homocyclic Carbon Rings... 

In additirm to the numerous homocyclic oligosilanes described above also a fair number of heterooligosilanes have been prepared and studied. Most of these compounds were synthesized by one of the two complementary strategies. Reacticm of either a,o)-dielectrophilic or a,ci)-dinucleophilic chains with respective dinucleophiles or dielectrophiles usually leads to cyclic compounds. 

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