1,2- and 1,1-Migratory Insertion Reactions of Silylated Germylene Adducts

Abstract

The reactions of the PMe3 adduct of the silylated germylene [(Me3Si)3Si]2Ge: with GeCl2·dioxane were found to yield 1,1-migratory insertion products of GeCl2 into one or two Ge–Si bonds. In a related reaction, a germylene was inserted with tris(trimethylsilyl)silyl and vinyl substituents into a Ge–Cl bond of GeCl2. This was followed by intramolecular trimethylsilyl chloride elimination to another cyclic germylene PMe3 adduct. The reaction of the GeCl2 mono-insertion product (Me3Si)3SiGe:GeCl2Si(SiMe3)3 with Me3SiC≡CH gave a mixture of alkyne mono- and diinsertion products. While the reaction of a divinylgermylene with GeCl2·dioxane only results in the exchange of the dioxane of GeCl2 against the divinylgermylene as base, the reaction of [(Me3Si)3Si]2Ge: with one GeCl2·dioxane and three phenylacetylenes gives a trivinylated germane with a chlorogermylene attached to one of the vinyl units.

Access to a Variety of Ge(II) and Sn(II) Compounds through Substitution of Hypersilyl Moiety

“…One way to displace the silyl group is through the elimination of silyl-chloride or bromide. In this regard, Marschner and co-workers demonstrated the synthesis of a five-membered digermaheterocycle from a germylene through Me 3 SiCl elimination . The reaction of 3 with Cy 2 PCl and t Bu 2 PCl led to the phosphino germylenes, 5 and 6 , along with the concomitant elimination of (Me 3 Si) 3 SiCl (Scheme ).…”

“…In this regard, Marschner and co-workers demonstrated the synthesis of a five-membered digermaheterocycle from a germylene through Me 3 SiCl elimination. 21 The reaction of 3 with Cy 2 PCl and tBu 2 PCl led to the phosphino germylenes, 5 and 6, along with the concomitant elimination of (Me 3 Si) 3 SiCl (Scheme 2). To our knowledge, phosphino germylenes reported earlier, mostly supported by β-diketiminate ligands, were prepared via salt metathesis of chlorogermylenes with alkali metal phosphides.…”

The Hypersilyl Substituent in Heavier Low‐Valent Group 14 Chemistry

“…Alkyne insertion was investigated on 87 as it has two weak bonds: GeÀ Si and GeÀ Ge, and the reaction led to the formation of two products (91 and 92). [40] 91 is the double regioselective 1,2-insertion of Me 3 SiC�CH on the two GeÀ Si bonds, while 92 is the single alkyne insertion product (Scheme 27). Please note here that one of the Ge is not coordinated by PMe 3 (Ge is in + 4 oxidation state), hence insertion of alkyne in this bond is surprising.…”

Unsymmetrical sp2‐sp3 Disilenes

“…To name a few, Braunschweig and co‐workers reported a series of B≡N, B≡O, B=C, B=B species using Me 3 SiX elimination [11–14] . Marschner and co‐workers demonstrated the formation of a five‐membered digermaheterocycle from a germylene through Me 3 SiCl elimination [15] . To our surprise, the reaction of 1 with disubstituted aliphatic chlorophosphines with an α‐H atom ( i Pr 2 PCl and Cy 2 PCl) led to the formation of unsymmetrical disilenes ( 2 – 4 ).…”

“…[11][12][13][14] Marschner and co-workers demonstrated the formation of a five-membered digermaheterocycle from a germylene through Me 3 SiCl elimination. [15] To our surprise, the reaction of 1 with disubstituted aliphatic chlorophosphines with an a-H atom (iPr 2 PCl and Cy 2 PCl) led to the formation of unsymmetrical disilenes (2)(3)(4). Aliphatic chlorophosphine without any a-H atom, such as tBu 2 PCl led to a new amidinatosilylene (5) as a major product along with an unsymmetrical disilene (6).…”