“…[61,62] The resulting high reactivity makes such speciesi nteresting precursors in various brancheso fc hemistry.T he number of preparative approaches to strained unsaturated silacycles, however,i sf airly limited and of narrow applicability: (1) the reduction of halosilanes, [11, 20h, 59, 63] (2) thermalo rp hotochemical interconversions, [64] (3) cycloaddition of disilynes with alkenes [65] and (4) reactions of metallosilyl reagents. [8,45,52,66] In 1999, Kirae tal. and Sekiguchi's group reported the first stable cyclotrisilenes 68 and 72 a.C yclotrisilene 68 was obtained in the reduction of R 3 SiSiBr 2 Cl (R = SiMe 2 tBu) in as uspensiono fK C 8 in THF (Scheme 21).…”