Lanthanide-Catalyzed Synthesis of Cyclic Silicon-Containing Di- and Triperoxides
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hanide-Catalyzed Synthesis of Cyclic Silicon-Containing Di- and Triperoxides N. N. Makhmudiyarovaa,*, I. R. Ishmukhametovaa, and A. G. Ibragimova a
Institute of Petrochemistry and Catalysis, Russian Academy of Sciences, Ufa, 450075 Russia *e-mail: [email protected] Received March 17, 2020; revised March 28, 2020; accepted March 31, 2020
Abstract—An efficient method has been developed for the synthesis of di(tri)peroxysilacycloalkanes by cyclization of geminal bis-hydroperoxides and 1,1′-peroxybis(1-hydroperoxycycloalkanes) with bis(methoxymethyl)diphenylsilane in the presence of lanthanide catalysts. Conditions have been found for the reduction of diphenylhexaoxasiladispirocycloalkanes to diphenyltetraoxasiladispirocycloalkanes. Keywords: di(tri)peroxysilacycloalkanes, gem-bis-hydroperoxides, 1,1′-peroxybis(1-hydroperoxycycloalkanes), bis(methoxymethyl)diphenylsilane, cyclization, diphenylhexaoxasiladispirocycloalkanes, diphenyltetraoxasiladispirocycloalkanes, catalysis
DOI: 10.1134/S1070428020100024 Silicon-containing organic peroxides are widely used for the preparation of polymers [1–6] and as hydroxylating [7–9], peroxidizing [10–13], and oxidizing agents [11, 14]. Well known synthetic approaches to linear peroxides containing Si–O–O fragments are based on reactions of chlorosilanes with hydroperoxides under basic conditions [15, 16], peroxidation of unsaturated compounds [17, 18], and oxidation of silyl enolates with singlet oxygen and of silanes with ozone [19–21]. Fewer publications are available on the synthesis of cyclic peroxysilanes; among them, the synthesis of silicon-containing macrocyclic peroxides by reaction of geminal bis-hydroperoxides with di- and tetrachlorodisilanes in the presence of bases has attracted attention [22–24]. Our previous results on the synthesis of aza peroxides [25–30] allowed us to presume that siliconcontaining cyclic peroxides could be obtained by recyclization of pentaoxa heterocycles with silanes in the presence of lanthanide catalysts. However, the Sm(NO3)3·6H 2O-catalyzed reaction of 6,7,9,11,12pentaoxaspiro[4.7]dodecane with diphenylsilane gave no expected product, 9,9-diphenyl-6,7,11,12-tetraoxa9-silaspiro[4.7]dodecane. Simultaneously, we have demonstrated the possibility of synthesizing aza peroxides by reacting geminal bis-hydroperoxides with N,N-bis(methoxymethyl)aren(hetaren)amines using EuCl3/γ-Al2O3 as catalyst [30]. Likewise, bis(methoxymethyl)diphenylsilane (1) reacted with an equimolar
amount of 1,1-di(hydroperoxy)cyclopentane (2) (~20°C, THF, 6 h) in the presence of 5 mol % of EuCl3/γ-Al2O3 to afford 61% of expected 9,9-diphenyl6,7,11,12-tetraoxa-9-silaspiro[4.7]dodecane (9) (Scheme 1). No reaction occurred in the absence of a catalyst. The reaction was also carried out with other lanthanide salts and complexes [La(NO 3 ) 3 ·6H 2 O, TbCl3·6H2O, Ho(NO3)3·5H2O, DyCl3∙6H2O, NdCl3], and the highest yield (76%) of 9 was obtained in the presence of La(NO3)3·6H 2O. Therefore, all further experiments were performed using La(NO3)3·6H2O as catalyst. Under similar co
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