Ring compounds, large, synthesis considerations

Because of the unique properties of the cyclopropane ring, cyclopropylbenzene is a compound of considerable interest. Only one of the alternative methods 9 for the preparation of this compound has been reported to give more than 32% yield the procedure described affords an olefin-free product without a relatively laborious purification process. By its utilization of readily available starting materials, and by its applicability to the preparation of large quantities of product, this method of synthesis provides easy access to many cyclopropylbenzene derivatives.12... 

Cyclosiloxanes, (RjSiO), are compounds of considerable commercial importance as precursors to silicone polymers. Although a large number of ring sizes can be obtained by the hydrolysis of difunctional silanes, the first members of this series, the cyclodisiloxanes, were not known before the synthesis of tetramesitylcyclodisiloxane [230-233]. This compound is produced nearly quantitatively from tetramesityldisi-lene when the latter is simply exposed to atmospheric oxygen (Eq. 3.90) ... 

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