With carbonyl group

Another feature of the Pd—C bonds is the excellent functional group tolerance. They are inert to many functional groups, except alkenes and alkynes and iodides and bromides attached to sp carbons, and not sensitive to H2O, ROH, and even RCO H. In this sense, they are very different from Grignard reagents, which react with carbonyl groups and are easily protonated. 

Conjugation with olefinic or acetylenic groups lowers the frequency and raises the intensity. Conjugation with carbonyl groups usually has little effect on the position of absorption. 

In similar reactions, (12) with carbon—carbon double bonds that are conjugated with carbonyl groups gives cyclopropane derivatives (eq. 24) (48) ... 

Compounds with carbonyl groups or double bonds are moderately degradable and slow to acclimate. 

Many other organometaUic compounds also react with carbonyl groups. Lithium alkyls and aryls add to the ester carbonyl group to give either an alcohol or an olefin. Lithium dimethyl cuprate has been used to prepare ketones from esters (41). Tebbe s reagent, Cp2TiCH2AlCl(CH2)2, where Cp = clyclopentadienyl, and other metal carbene complexes can convert the C=0 of esters to C=CR2 (42,43). 

Both 1,2- and 2,1-benzisoxazoles with carbonyl groups in the 3-position show reactions such as those above, characteristic of the carbonyl function (67AHC(8)277,p. 296,329). 

Dinitrophenylhydrazine reacts with carbonyl groups with the elimination of water to yield hydrazones (I) and with aldoses or ketoses to yield colored osazones (II). 

This ketal is stable to several reagents that react with carbonyl groups (e.g., m-ClC6H4C03H, NH3, NaBH4, and MeLi). It is cleaved under neutral conditions. 

The epoxidation reaction usually takes place under mild conditions and with good to very good yield. Functional groups that are sensitive to oxidation should not be present in the starting material with carbonyl groups a Baeyer-Villiger reaction may take place. 

Bisorganomercury compounds with carbonyl groups in the P- and P -positions (10.68) give arylmercury chloride (10.67) together with the dimer (10.69) of the organic residue that is bounded to mercury in the starting material (Hu et al., 1991 yields 10.67 64-98%, 10.69 50-63%). 

Methylene coupling components with carbonyl groups in a,a-positions are very important, particularly acetoacetanilide derivatives (Scheme 12-40, X=NHAr), for the production of yellow monoazo dyes and pigments (Hansa Yellows see Zollinger, 1991, p. 180). 

The tetrahedral mechanism, often also called addition-elimination (Ar N - E), takes place with much less facility than with carbonyl groups, since the negative charge of the intermediate must be borne by a carbon, which is less electronegative than oxygen, sulfur, or nitrogen ... 

The N-labeled amines produced by partial and total reduction of the nitro groups in 2,4,6-trinitrotoluene reacted with carbonyl groups (quinones and ketones) in humic acid to produce a range of products (Thom and Kennedy 2002). 

Whereas a-chlorination of sulfones usually constitutes a problem, thiane oxides are easily chlorinated at the a-position by a wide spectrum of chlorinating agents. The mechanism is similar to that with carbonyl groups . 

Intramolecular condensation of phosphonate carbanions with carbonyl groups carried out under conditions of high dilution have been utilized in macrocycle syntheses. Entries 7 and 8 show macrocyclizations involving the Wadsworth-Emmons reaction. Entries 9 to 11 illustrate the construction of new double bonds in the course of a multistage synthesis. The LiCl/amine conditions are used in Entries 9 and 10. 

We have recently investigated X-ray structure of 3-methoxycarbonyl-[l,4,2] diazaphospholo[4,5-a]pyridine as first example of molecular structure determination for [l,4,2]diazaphosphole ring [84], The ester substituent lies strictly in the molecular plane with carbonyl group in the trans orientation with the formal C=P bond. Endocyclic P-N and P-C bonds are averaged between respective single and double bond lengths. 

Figure 1.70 AMBH is a hydrazide-containing compound that reacts with carbonyl groups to form hydrazone bonds. The free thiol can be used for subsequent conjugation reactions.

Hydrazide-containing PEG-biotinylation reagents provide reactivity with carbonyl groups (e.g., aldehydes) to label carbohydrates or glycoproteins via hydrazone bond formation (Figures 18.19 and 18.20). The hydrazide group also may be coupled with carboxylate-containing... 

Hydrazide groups can react with carbonyl groups to form stable hydrazone linkages. Derivatives of proteins formed from the reaction of their carboxylate side chains with adipic acid dihydrazide (Chapter 4, Section 8.1) and the water-soluble carbodiimide EDC (Chapter 3, Section 1.1) create activated proteins that can covalently bind to formyl residues. Hydrazide-modified enzymes prepared in this manner can bind specifically to aldehyde groups formed by mild periodate oxidation of carbohydrates (Chapter 1, Section 4.4). These reagents can be used in assay systems to detect or measure glycoproteins in cells, tissue sections, or blots (Gershoni et al., 1985). 

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