Grignard special

Since Grignard reagents can easily be obtained from aryl halides, they are of special value in the s nthesis of many aromatic compounds, particularly as, for reasons already stated (pp. 270, 276), aromatic compounds cannot generally be prepared by means of ethyl acetoacetate and ethyl malonate. 

The main use of organocadmium compounds is for the preparation of ketones and keto-esters, and their special merit lies in the fact that they react vigorously with acid chlorides of all types but add sluggishly or not at all to multiple bonds (compare addition of Grignard reagents to carbonyl groups). Some t3rpical syntheses are ... 

Special handling procedures have been described (39) for those cases where the Grignard reagent is purchased commercially (either in dmms or bulk) for use in a separate facihty. 

Addition of Grignard reagents to ketones and aldehydes was one of the reactions which led to the formulation of Cram s rule. Many ketones and aldehydes have subsequently been examined to determine the degree of stereoselectivity. Cram s rule is obeyed when no special complexing functional groups are present near the reaction site. One series of studies is summarized in Table 8.2. 

Since the ethyl Grignard reagent is used in large excess, no special precautions need to be taken in the transfer to prevent the loss of small amounts. 

There are many ways to get a negative charge on a carbon atom. Later in this course, you will spend a lot of time learning about special C compounds. For now, we will just learn about one such compound, called a Grignard reagent ... 

Vinylic sulfones undergo the same reaction especially when allylic, benzylic or t-alkylithium reagents are employed. One case of a vinyl sulfone deserves special mention - . When phenyl trans-3-bromopropenyl sulfone is treated with certain Grignard reagents it undergoes an alkylating cyclization ... 

Grignard reactions are so sensitive to acidic compounds that special care must be taken to exclude moisture from the apparatus and anhydrous ether must be used as the solvent. 

Uses Artificial resins perfumery solvent adhesives protective coatings special fuel organic synthesis (Grignard and Reppe reactions). 

Instead of adding special equipment to individual production trains, it is also possible to place them centrally in the dry or wet section of the plant, respectively. In this way they can be connected as needed to different production trains. Another option is to create semispecihc production trains, For example, for hydrogenations, phosgenizations, Friedel-Crafts alkylations, and Grignard reactions. 

Alcohols are the most important precursors in the synthesis of carbonyl compounds, being readily available. More complex alcohols are prepared by reaction of Grignard reagents with simpler carbonyl compounds. Ordinarily MnO and Cx OY in acid are used to oxidize 2° RjCHOH to RjCO. However, to oxidize 1° RCHjOH to RCHO without allowing the ready oxidation of RCHO to RCOOH, requires special reagents. These include (a) pyridinium chlorochromate (pcc),... 

A. Vaupel, F. Langer, V. Malakov and P. Knochel, Chap. A1 in Reference 62c, pp. 325-346. For the Ni-catalyzed Grignard aryl-aryl coupling producing special classes of biaryls, see ... 

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