TY  - JOUR
A1  - Georg, Isabelle
A1  - Bursch, Markus
A1  - Stückrath, Julius B.
A1  - Alig, Edith
A1  - Bolte, Michael
A1  - Lerner, Hans-Wolfram
A1  - Grimme, Stefan
A1  - Wagner, Matthias
T1  - Building up strain in one step: synthesis of an edge-fused double silacyclobutene from an extensively trichlorosilylated butadiene dianion
T2  - Angewandte Chemie
N2  - The exhaustive trichlorosilylation of hexachloro-1,3-butadiene was achieved in one step by using a mixture of Si2Cl6 and [nBu4N]Cl (7:2 equiv) as the silylation reagent. The corresponding butadiene dianion salt [nBu4N]2[1] was isolated in 36 % yield after recrystallization. The negative charges of [1]2− are mainly delocalized across its two carbanionic (Cl3Si)2C termini (α-effect of silicon) such that the central bond possesses largely C=C double-bond character. Upon treatment with 4 equiv of HCl, [1]2− is converted into neutral 1,2,3,4-tetrakis(trichlorosilyl)but-2-ene, 3. The Cl− acceptor AlCl3, induces a twofold ring-closure reaction of [1]2− to form a six-membered bicycle 4 in which two silacyclobutene rings are fused along a shared C=C double bond (84 %). Compound 4, which was structurally characterized by X-ray crystallography, undergoes partial ring opening to a monocyclic silacyclobutene 2 in the presence of HCl, but is thermally stable up to at least 180 °C.
KW  - Carbanions
KW  - Cyclization
KW  - Heterocycles
KW  - Silacyclobutenes
KW  - Silylation
Y1  - 2020
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/63834
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-638348
SN  - 1521-3773
N1  - The authors are grateful to the Evonik Resource Efficiency GmbH, Rheinfelden (Germany), for the generous donation of Si2Cl6. I.G. wishes to thank the Evonik Foundation for a Ph.D. 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  - 59
IS  - 37
SP  - 16181
EP  - 16187
PB  - Wiley-VCH
CY  - Weinheim
ER  -