Organic synthesis examples

Arylmetallic compounds have various, but not very widely used, applications in organic synthesis. Examples are acyl-de-metallation reactions using either dicobalt octacarbonyl in tetrahydrofuran (Seyferth and Spohn, 1969 Scheme 10-92), or carbon monoxide and a rhodium catalyst (Larock and Hershberger, 1980). 

New applications continue to demonstrate the enormous versatility of RCM for organic synthesis. Examples include triple ring closing (Eq. 48) and alkyne metathesis, an example being that of cross-metathesis that provides an efficient synthetic strategy for prostaglandin E2 (Eq. 49). Amines and alcohols deactivate metathesis catalysts, but their protection as ethers, esters, and amides allows them to be incorporated into the designated transformation. 

The oxidative coupling of enolates, reported for the first time in 1935, represents an interesting application of enolates in organic synthesis. Examples of these reactions. 

Double-bond isomerization has been exploited as a desired reaction in organic synthesis examples include the synthesis of steroids. It is also an undesired side reaction of industrially relevant reactions such as hydroformylation (cf. Section 2.1.1), hydrogenation (cf. Section 2.2), and hydrosilyation (cf. Section 2.6), it is a subject of current interest [34—36]. Two promising developments are worth mentioning here because they yielded highly selective catalysts which are, at the same time, easy to handle. 

The kinetics of many the reactions of radicals with tin hydrides have been studied because of their importance in organic synthesis. Examples are given in Table 15-5, and a more extensive list is given in a recent review by Chatgilialoglu and Newcomb.111 The solvents are not quoted in the table, but in general they are non-polar (e.g. octane or benzene) and the rates are not sensitive to the nature of the solvent. 

Figure 8.11. The data arrays of the peat example (5 x 7 x 21) and the batch organic synthesis example (14 x 13 x 1050) shown schematically.

Figure 8.12. A PARAFAC loading from the batch organic synthesis example (full line) compared with a pure mixture spectrum (dashed line). The data are shown in Savitzky-Golay first derivative form. For a large number of variables, continuous curves are an excellent visualization form.

In Section 24.12, we introduced alkene (olefin) metathesis, i.e. metal-catalysed reactions in which C=C bonds are redistributed. The importance of alkene and alkyne metathesis was recognized by the award of the 2005 Nobel Prize in Chemistry to Yves Chauvin, Robert H. Grubbs and Richard R. Schrock for the development of the metathesis method in organic synthesis . Examples of alkene metathesis are shown in Figure 27.3. The Chauvin mechanism for metal-catalysed alkene metathesis involves a metal alkyli-dene species and a series of [2 + 2]-cycloadditions and cycloreversions (Figure 27.4). Scheme 27.6 shows the mechanism for alkyne metathesis which involves a high oxidation state metal alkylidyne complex, L M=CR. 

Organometallic complexes in organic synthesis - Examples of applications 491... 

ORGANOMETALLIC COMPLEXES IN ORGANIC SYNTHESIS - EXAMPLES OF APPLICATIONS... 

Chapter 21 - Organometallic complexes in organic synthesis Examples of applications... 

---