Speicherung des labilen Silaethens Me₂Si=C(SiMe₃)₂ mit N-Trimethylsilyl-benzophenonimin Ph₂C=NSiMe₃ / Storing of the Labile Silaethene Me₂Si=C(SiMe₃)₂ with N-Trimethylsilyl-benzophenoneimine Ph₂C=NSiMe₃

Abstract

N-Trimethylsilyl-benzophenoneimine Ph 2 C=NSiMe 3 is able to “store" the silaethene Me 2 Si = C(SiMe 3 ) 2 (1). produced from Me 2 SiF-CLi(SiMe 3 ) 2 , under formation of a [2+4]- and [2+2]-cycloadduct (2, 3), respectively. Above 60 °C (above 120 °C) 2 or 3 by the way of 1 transform into a 1:5 mixture of 2 and 3 (into a 1:1 mixture of the dimer of 1 and the insertion product of 1 into the SiN-bond of Ph 2 C=NSiMe 3 ). In the presence of 2,3-dimethyl-1.3-butadiene (dmb), 2 or 3 form by way of the reaction of the intermediate 1 with dmb a [2 + 4]-cycloadduct (75%) and an ene reaction product (25%). The rate constants of the first order decomposition of 2 or 3 in the presence of dmb (80 °C. solvents like Et 2O, Q 6 H 6 are in the order of 2x10 -4 s -1 (τ 1/2 ca. 1 h) and 3x10 - 5 s -1 (τ 1/2 ca. 6 h). respectively.