Xenon difluoride (XeF2) reacts with alcohols to form unstable alkoxyxenon fluoride intermediates (ROXeF). The regio- and stereo-chemistry of products from reaction of ROXeF with indene were determined. Alkoxyxenon fluorides [R = CH3, (CH3)2CH, and (CH3)3C] react as positive oxygen electrophiles (OE) when boron trifluoride–ether is used as catalyst. However, these alkoxyxenon fluorides react as apparent fluorine electrophiles (FE) with proton catalyst (hydrogen fluoride generated in situ). Reactions of XeF2 and alcohols with electron-withdrawing substituents give alkoxyxenon fluorides which add to indene as an OE species even though boron trifluoride–ether was not used as catalyst. Reactions of XeF2 with polynitroaliphatic alcohols and indene give rapid polymerization of indene rather than alkoxyfIuorination.