TRITOLYLARSONIUM AND TRIS(METHOXYPHENYL)ARSONIUM YLIDES THE EFFECTS OF ortho-SUBSTITUENTS IN TRIARYLARSONIUM GROUPS ON THE PROPERTIES OF YLIDES

Article abstract of DOI:10.1016/S0040-4020(01)91822-8

A number of tritolylarsonium and tris(methoxyphenyl)arsonium cyclopentadienylides and other ylides have been prepared and their properties (basicity, NMR spectra, reactions with aldehydes and nitrosobenzene, acetylation, and methanolysis) have been investigated.Substituents in the m- or p-positions of triarylarsonium groups have little effect on properties, but o-substituents result in markedly lower reactivity and lower basicity, and these ylides were also more difficult to prepare.NMR spectra gave indication of crowding in some of these o-substituted ylides.The effects of the o-substituents are discussed. p-Methyl- and p-methoxy-substituents increased the proportion of anil to ketoxime formed in reactions with nitrosobenzene, but the o-methoxy analogue gave only ketoxime.