Preparation and Reactions of Organometallic Compounds

In this section, some recent uses of pyrans in synthesis are described. Much of the chemistry of this class of compounds involves Diels-Alder cycloadditions, metal- and thermal-assisted reorganization reactions, and the preparation and reactions of organometallic derivatives. The chemistry of the pyrylium salts, useful precursors to substituted aromatics (B-64MI11600), will not be discussed here. 

A52. A. Schonberg, G. O. Schenk, and O.-A. Neumuller, Preparative Organic Photochemistry, 2nd ed. Springer, Berlin, 1968. Chapter 45, pp. 459-470 Photochemical formation and reactions of organometallic compounds. 

Each of the following compounds can be prepared from reactions of organometallic reagents and readily available starting materials. Identify the appropriate organome-... 

Preparation and Reactions of Organocobalt(lII) Complexes, 11, 331 Radiochemistry of Organometallic Compounds, 11, 207... 

The fairly recent literature has included a review of the preparation and reactions of allyl and butenyl Grignard reagents (5), a review of the reactions of allylic organometallic compounds (II), and a review of organomagnesium rearrangements, in which allylic derivatives were discussed in some detail (29). Since more recent publications do not appear to include new information that would significantly modify earlier conclusions, the previous discussions should suffice. 

The reaction between metals and organic halides is often suitable for the synthesis of organometallic compounds of the most electropositive elements. On a laboratory scale, the derivatives of Li. Mg and Al, which are very important in synthetic work, are usually prepared in this way. Some illustrations of the method are given briefly here more detailed discussion of the preparation and properties of the compounds involved appears in Chapter 3. 

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