Catalytic tritiations

Carbon-carbon multiple bonds are most commonly reduced by means of catalytic tritiation methods. Polarized multiple bonds such as those of carbonyl, carboxyl and nitrile groups are less often reduced by catalytic tritiation, since the use of tritide reagents is often more convenient and can provide greater selectivity (see Section 4.3). 

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Prockop and others (258, 259) prepared a sample of [3,4- H2]proline 252, Hg = Ht, = H, by catalytic tritiation of 3, 4-dehydroproline, and while acknowledging that some randomization of label might occur in this process. 

Catalytic tritiation of compounds containing vinylic protons under... 

There is a much wider variety of indirect replacement approaches. In most cases these approaches introduce the labels at structurally predefined positions generated by (formally) oxidative processes, which are then followed in a second step by reductive operations. Examples of such approaches preferentially designed for the introduction of tritium include halogenation followed by tritiodehalogenation, the introduction of carbon-carbon multiple bonds followed by catalytic tritiation, the oxidation of carbon-heteroatom bonds followed by reduction using tritide reagents, etc. These approaches, which do not alter the skeleton of the target in the process, are discussed in Chapter 4, Sections 1-3 and Chapter 10, Sections 10.1.1.2. ... 

Of even more practical relevance is the incorporation of excess tritium during the catalytic tritiation of 4,5-dehydroleucine (A -Leu) and of peptides containing this precursor of [ HJleucine, leading to specific activities of up to 200 Ci/mmol. N-Boc-A -Leu (5) has been subjected to catalytic tritiation using palladium catalysts then the... 

Oxygen and nitrogen functions are rarely of concern in catalytic tritiations of olefinic substrates, as long as they are not located in benzylic or allylic positions. If they are, tritiolytic cleavage may occur, but this can often be avoided by utilizing rhodium or... 

Figure 4.21 Catalytic tritiation of a carbonyl function in the synthesis oftritiated o-ribose...

Figure 11.42 Diastereoselective a-methylation of an unlabeled (4R,5S)-3-acyl-4-methyl-5-phenyloxazolidin-2-onecontainingadoublebond for subsequentintroduction of label through catalytic tritiation...

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