The molecular dynamics and cycloaddition chemistry of tris(1-indenyl)allylsilane Part 1Generation of the first crystallographically characterized tris(benzonorbornyl)silane

The preparation, characterization and molecular dynamics of tris(1-indenyl)allylsilane, 5, are presented. Data obtained from single selective inversion and 1H–1H EXSY NMR experiments demonstrate that 5 is indeed fluxional (ΔG∽25 kcal mol-1). Moreover, a solution of 5 stirred with three equivalents of tetracyanoethylene yields tris(5,6-benzo-2,2,3,3-tetracyanobicyclo[2.2.1]heptan-7-yl)allylsilane, 7, an observation that is consistent with the sequential generation and trapping of isoindene intermediates in a [1,5]-silatropic shift mechanism. The triple cycloadduct, 7, represents what is believed to be the first crystallographically characterized tris(benzonorbornyl)silane.