trans-dietherification of cyclic alkenes using silver(I) salts, iodine, and alcohol

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Description: A mixture of two molar equivalents of silver perchlorate, one molar equivalent each, of iodine and sym-collidine plus an excess of an alcohol in methylene chloride at ambient temperature is an effective reagent system for the conversion of cyclic alkenes to vic-trans diethers. The reaction proceeds in higher yields, and with fewer side products than previously reported related reactions. The products are consistent with the mechanistic scheme generally accepted for Prevost type reactions. Although, the use of iodine, sym-collidine and two equivalents of silver perchlorate as a reagent system affords a one-pot formation of the trans-diether. trans-Dietherification has also been achieved in a step-wise manner by reacting bis-sym-collidine iodine(I) perchlorate with the alkene and alcohol in methylene chloride with the initial formation of the corresponding vic-trans-iodoether. Further addition of one equivalent of silver perchlorate to the reaction mixture results in formation of the trans-diether, with retention of configuration. The efficacy of efforts to optimize product yield and purity was monitored by gas chromatography (GC) using a macrocapillary fused silica column. The products of the reaction were stable and easily separable under the chromatographic conditions utilized. Minor side product identification was achieved by GC/MS. Structural and stereochemical information on isolated products was provided using $\sp1$H and $\sp{13}$C NMR spectroscopy. Correlated $\sp1$H NMR spectroscopy (COSY) and DEPT NMR studies were utilized to assist in structure determination.
Language: English
Format: Degree Work