Stereochemistry of the addition of diarylsilylenes to cis- and trans-2-butenes

Recent Advances in Silylene Chemistry: Small Molecule Activation En-Route Towards Metal-Free Catalysis

“…Notable earlier examples include the seminal bis(tri-tert-butylsilyl) silylene, shown to exist as a triplet in the ground state on the basis of EPR investigations [80]; or the earlier reported singlet bis(diisopropylamino)silylene [81]. Other seminal examples include Mes 2 Si: [82] and Trip 2 Si: [83] which are only stable until 77 K and have been characterised by low-temperature UV-vis spectroscopy. The observation of a triplet ground state in the transient bis(tri-tertbutylsilyl)silylene is noteworthy, since silylenes generally exhibit a singlet ground state.…”

Silylfullerenes.

“…This is confirmed by the 29Si NMR peak at 6 = -72.74, since a typical chemical shift for a silicon atom in a silirane ring appears at high field ranging from S = -50 to S = -85. 10 The experimental finding for 2a was confirmed by AM1 molecular orbital calculations" on the reaction of C60 and silylenes Ph2Si: and H2Si: (Table 1). 9 Ph2Si: and H2Si: add across the junction of two six-membered rings in C60 to give siliranes 2d and 2e (1, 2-adducts), with an exothermicity of 61.3 and 78.0 kcal/mol, respectively.…”

“…9 The 13C NMR signal at S = 71.12, which is ascribed to the spa carbons of the silirane ring, strongly sup- ports 2a rather than silamethano [10]annulene 6a'; an sp2 CSi should give rise to a signal below 6 = 130. This is confirmed by the 29Si NMR peak at 6 = -72.74, since a typical chemical shift for a silicon atom in a silirane ring appears at high field ranging from S = -50 to S = -85.…”

Steric effects on the dialkyl substituted X2C2Si silylenes: A theoretical study

“…Chemical species which involve divalent silicon atoms, silylenes, are key intermediates in numerous thermal and photochemical reactions of organosilicon compounds [4]. Besides, much interest has been focused on their bonding properties and reactivities such as addition to olefins [11,12], alkynes [13], isocyanides [14], and transition metal complexes [15] in connection with the reactivities of carbenes. The multiple-bond compounds including second period elements such as olefin, imine (Schiff base), ketone, acetylene, nitrile, etc.…”