ON THE REDUCTION OF 4-OXO-4H-BENZOPYRAN-3-CARBALDEHYDES: GLOBAL AND LOCAL ELECTROPHILICITY PATTERNS‡

RAMIRO ARAYA-MATURANA, JORGE HEREDIA-MOYA, CARLOS A. ESCOBAR, PATRICIA PÉREZ
2004 Journal of the Chilean Chemical Society (Print)  
The theoretical global and local electrophilicity patterns of substituted and chelated 4oxo-4H-benzopyran-3-carbaldehydes (formylchromones) have been evaluated using the electrophilicity index proposed by Parr et al [J. Am. Chem. Soc. 1999, 121, 1922. The complexation of formylchromones with aluminum predicts a strong electrophilic character of these compounds against nucleophiles. Local response at the active sites may also be assessed in terms of a global contribution described by the global
more » ... ibed by the global electrophilicity, and a local contribution described by the variations in electrophilic Fukui function at those sites. The highest local electrophilicity is found at the formyl group of the chelated formylchromones, in spite of that, the highest positive charge is located on the pyrone carbonyl group. This result is consistent with the experimental observed reactivity displayed by 4-oxo-4H-benzopyran-3-carbaldehydes in the presence of 2-propanol and alumina.
doi:10.4067/s0717-97072004000100007 fatcat:dej37tft4vgzbdko55rhclznam