Cumulative Subject reactivity

Allene is a versatile functionality because it is useful as either a nucleophile or an electrophile and also as a substrate for cycloaddition reactions. This multi-reactivity makes an allene an excellent candidate for a synthetic manipulations. In addition to these abilities, the orthogonality of 1,3-substitution on the cumulated double bonds of allenes enables the molecule to exist in two enantiomeric configurations and reactions using either antipode can result in the transfer of chirality to the respective products. Therefore, the development of synthetic methodology for chiral allenes is one of the most valuable subjects for the synthetic organic chemist. This chapter serves as an introduction to recent progress in the enantioselective syntheses of allenes. Several of the earlier examples are presented in excellent previous reviews [ ] ... 

These studies demonstrated that DNA-binding can be a reliable probe of metabolic activation. In contrast to studies of metabolites per se, which usually involve large numbers of metabolite intermediates, DNA-binding monitors only chemically reactive metabolites. Also, if there is no selective repair of specific adducts, DNA-binding monitors the cumulative production of metabolites over time, while direct measurement of metabolites can show the metabolite spectrum only at the time observed. This can be particularly critical for studies of activation of complex chemicals such as polycyclic aromatic hydrocarbons whose primary metabolites are subject to secondary and tertiary metabolism (8). 

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