TY  - JOUR
A1  - Georg, Isabelle
A1  - Bursch, Markus
A1  - Endeward, Burkhard
A1  - Bolte, Michael
A1  - Lerner, Hans-Wolfram
A1  - Grimme, Stefan
A1  - Wagner, Matthias
T1  - The power of trichlorosilylation: isolable trisilylated allyl anions, allyl radicals, and allenyl anions
T2  - Chemical science
N2  - Treatment of hexachloropropene (Cl2C[double bond, length as m-dash]C(Cl)–CCl3) with Si2Cl6 and [nBu4N]Cl (1 : 4 : 1) in CH2Cl2 results in a quantitative conversion to the trisilylated, dichlorinated allyl anion salt [nBu4N][Cl2C[double bond, length as m-dash]C(SiCl3)–C(SiCl3)2] ([nBu4N][1]). Tetrachloroallene Cl2C[double bond, length as m-dash]C[double bond, length as m-dash]CCl2 was identified as the first intermediate of the reaction cascade. In the solid state, [1]− adopts approximate Cs symmetry with a dihedral angle between the planes running through the olefinic and carbanionic fragments of [1]− of C[double bond, length as m-dash]C–Si//Si–C–Si = 78.3(1)°. One-electron oxidation of [nBu4N][1] with SbCl5 furnishes the distillable blue radical 1˙. The neutral propene Cl2C[double bond, length as m-dash]C(SiCl3)–C(SiCl3)2H (2) was obtained by (i) protonation of [1]− with HOSO2CF3 (HOTf) or (ii) H-atom transfer to 1˙ from 1,4-cyclohexadiene. Quantitative transformation of all three SiCl3 substituents in 2 to Si(OMe)3 (2OMe) or SiMe3 (2Me) substituents was achieved by using MeOH/NMe2Et or MeMgBr in CH2Cl2 or THF, respectively. Upon addition of 2 equiv. of tBuLi, 2Me underwent deprotonation with subsequent LiCl elimination, 1,2-SiMe3 migration and Cl/Li exchange to afford the allenyl lithium compound Me3Si(Li)C[double bond, length as m-dash]C[double bond, length as m-dash]C(SiMe3)2 (Li[4]), which is an efficient building block for the introduction of Me, SiMe3, or SnMe3 (5) groups. The trisilylated, monochlorinated allene Cl3Si(Cl)C[double bond, length as m-dash]C[double bond, length as m-dash]C(SiCl3)2 (6), was obtained from [nBu4N][1] through Cl−-ion abstraction with AlCl3 and rearrangement in CH2Cl2 (1˙ forms as a minor side product, likely because the system AlCl3/CH2Cl2 can also act as a one-electron oxidant).
Y1  - 2021
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/63548
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-635482
SN  - 2041-6539
N1  - I. G. wishes to thank the Evonik Foundation for a PhD grant. This work was partially funded by the Bundesministerium für Wirtschaft und Energie through the WIPANO grant number 03THW10K19. The German Research Foundation (DFG) is gratefully acknowledged for financial support through a Gottfried Wilhelm Leibniz prize to S. G.
VL  - 12
IS  - 37
SP  - 12419
EP  - 12428
PB  - RSC
CY  - Cambridge
ER  -