ACTIVATION OF SILICON-HYDROGEN, SILICON-OXYGEN, SILICON-NITROGEN BONDS IN HETEROGENEOUS PHASE SOME NEW METHODS IN ORGANIC SYNTHESIS

Article abstract of DOI:10.1016/S0040-4020(01)88599-9

Anionic activation of Si-H, Si-O and Si-N bonds by fluoride ions under heterogeneous conditions is reported: Si-H activated by KF or CsF is a powerful and selective reducing reagent; the carbonyl group of aldehydes, ketones or esters can be reduced without reduction of other functional groups (C=C, NO2, Br, amido).Furthermore, selective reductions of aldehydes in the presence of ketones and ketones in the presence of carboxylic esters are also possible.CsF in the presence of Si(OR)4 is found to be very efficient in promoting Michael additions of monoketones andarylacetonitriles on different kinds of Michael acceptors such as α, β unsaturated ketones, esters, nitriles and even amides.This constitutes an extension of Michael reaction since the addition occurs even with crowded ketones.N,N bis(silyl)enamines activated by fluoride ions react with carbonyl compounds and provide an interesting route to 2-aza-1,3 dienes.