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Building up Strain in One Step: Synthesis of an Edge‐Fused Double Silacyclobutene from an Extensively Trichlorosilylated Butadiene Dianion
Author(s) -
Georg Isabelle,
Bursch Markus,
Stückrath Julius B.,
Alig Edith,
Bolte Michael,
Lerner HansWolfram,
Grimme Stefan,
Wagner Matthias
Publication year - 2020
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202006463
Subject(s) - strain (injury) , 1,3 butadiene , enhanced data rates for gsm evolution , chemistry , materials science , computer science , biology , organic chemistry , artificial intelligence , catalysis , anatomy
The exhaustive trichlorosilylation of hexachloro‐1,3‐butadiene was achieved in one step by using a mixture of Si 2 Cl 6 and [ n Bu 4 N]Cl (7:2 equiv) as the silylation reagent. The corresponding butadiene dianion salt [ n Bu 4 N] 2 [ 1 ] was isolated in 36 % yield after recrystallization. The negative charges of [ 1 ] 2− are mainly delocalized across its two carbanionic (Cl 3 Si) 2 C 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 AlCl 3 , 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.