STUDIES OF ORGANOMETALLIC COMPOUNDS CONTAINING CALCIUM, MAGNESIUM AND PLATINUM
Abstract
Section A. Reduction of Organic Compounds with Calcium in Amines. Reductions of organic Compounds by an interesting compound, calcium hexammine, under optimized conditions were explored. As a consequence, a new reducing system involving calcium in amines was discovered, wherein the reducing property of calcium was demonstrated to resemble closely the synthetically useful lithium-mixed amine combination. Moreover, unlike the lithium-amine reducing system, the reduction with calcium was shown to be mild enough to minimize reduction and isomerization of isolated double bonds. Comparison of the two methods and the possible mechanisms for calcium reductions were presented. Section B. Addition of Allylic Grignard Reagents to Homoallylic Alcohols. Structural Effects on Addition and Cyclization. Addition of allylic Grignard reagents to homoallylic alcohols under normal conditions was shown to yield acyclic addition products and cyclobutanes. The latter resulted from the addition of the more substituted end of the allylic system in the Grignard reagent to the olefinic carbons of the homoallylic alcohols followed by cyclization. The proportion of each product was remarkably dependent upon the structures of the Grignard reagents and also the homoallylic alcohols. The kinetics and mechanisms of each step were discussed. In addition, the consistent stereochemistry of the cyclobutane products, which was confirmed by high field NMR analyses and indirect syntheses of four possible compounds, showed that the addition and cyclization steps had been stereospecific along with unusual retention of configuration of the carbon-magnesium bonds. Section C. The Use of Platinum Compounds as Useful Reagents in Organic Preparations. In view of the increasing utility of platinum metal catalysts in organic reactions, possible uses of modern analytical arsenals involving Pt-NMR, Fourier-transform IR, XPS and Organic SIMS for such research were discussed in addition to brief reviews on individual methodology. Thus, the composition of the highly heralded "Speier catalyst" which has been widely used in academic and industrial hydrosilylations was studied using the aforementioned techniques. Also, the general reaction patterns of chloroplatinic acid with alcohols were studied; initial reduction of the Pt(IV) species to H(,2)PtCl(,4) and subsequent dehydration to form olefins or allylic ethers followed by complexation of the Pt(II) compound with the resulting olefins were observed. Finally, studies on the reactions of unstabilized platinum complexes with silicon hydrides were initiated. Thus, compounds of a general type of {n-Bu(,4)N}(,2){Pt(SiR(,3))(,4)} were found to form in the reactions of a Zeisedimer type compound with trichlorosilane and dichloromethylsilane in the presence of excess tetrabutylammonium chloride. These products were verified by the analytical methods mentioned above. A rationalization of the formation of the tetrasilylplatinum dianion and some relevant discussion were presented.
Degree
Ph.D.
Subject Area
Chemistry
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