The reactivity of BTS (x = 1) and PTS (x = 0) towards charged electrophiles has been studied in the gas phase with the aim of assessing the activating and directive properties of the Me,Si(CH,), group in a solvent-free environment. BTS is confirmed to be highly activated towards electrophilic attack, which is directed to the ortho/para positions, consistent with a PA value of 200 +/- 1 kcal mol(-1). Ipso attack followed by desilylation is a dominant pathway in the reactions of PTS, tending to obscure its intrinsic reactivity. However, the reaction of a mild methylating agent, Me(2)Cl(+), yields a meaningful reactivity scare: BTS > p-xylene > PTS > toluene.
Gas Phase Reactivity of Aromatic Silanes. The Reaction of Ph(CH2)xSiMe3 (x = 0, 1) with Cationic Electrophiles / Crestoni, Maria Elisa; Fornarini, Simonetta; G., Occhiucci. - In: JOURNAL OF ORGANOMETALLIC CHEMISTRY. - ISSN 0022-328X. - STAMPA. - 465:(1994), pp. 109-118. [10.1016/0022-328X(94)87044-6]