Striking stability of a substituted silicon(II) bis(trimethylsilyl)amide and the facile Si-Me bond cleavage without a transition metal catalyst. 
Silicon(II) bis(trimethylsilyl)amide (LSiN(SiMe(3))(2), L= PhC(NtBu)(2)) (2) has been synthesized by the reaction of LSiHCl(2) with KN(SiMe(3))(2) in 1:2 molar ratio in high yield where 1 equiv of the latter functions as a dehydrochlorinating agent.  2 exhibits a high stability up to 154 °C and can be handled in open air for a short period of time without any appreciable decomposition.  An amazing five-membered cyclic silene (3) results from the cleavage of one Si-Me bond of 2 with an adamantyl phosphaalkyne.  3 is the first example of a heavy cyclopentene derivative which consists of four different elements, C, N, Si, and P. Both compounds are characterized by multinuclear NMR spectroscopy, EI-mass spectrometry, and single crystal X-ray diffraction studies.