Synthesis and Reactivity towards DIBAL‐H of Cyclo‐Siloxanes cyclo‐[R2SiOSi(Ot‐Bu)2O]2, cyclo‐(t‐BuO)2Si(OSiR2)2O,and cyclo‐R2Si[OSi(Ot‐Bu)2]2O (R = Me,Ph) |
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Authors: | Jens Beckmann Dainis Dakternieks Andrew Duthie Edward R T Tiekink |
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Abstract: | The six‐, eight‐ and twelve‐membered cyclo‐siloxanes, cyclo‐R2SiOSi(Ot‐Bu)2O]2 (R = Me ( 1 ), Ph ( 2 )), cyclo‐(t‐BuO)2Si(OSiR2)2O (R = Me ( 3 ), Ph ( 4 )), cyclo‐R2SiOSi(Ot‐Bu)2]2O (R = Me ( 5 ), Ph ( 6 )) and cyclo‐(t‐BuO)2Si(OSiMe2)2O]2 ( 3a ) were synthesized in high yields by the reaction of (t‐BuO)2Si(OH)2 and (t‐BuO)2SiOH]2O with R2SiCl2 and (R2SiCl)2O (R = Me, Ph). Compounds 1 — 6 were characterized by solution and solid‐state 29Si NMR spectroscopy, electrospray mass spectrometry and osmometric molecular weight determination. The molecular structure of 4 has been determined by single crystal X‐ray diffraction and features a six‐membered cyclo‐siloxane ring that is essentially planar. The reduction of 1 — 6 with i‐Bu2AlH (DIBAL‐H) led to the formation of the metastable aluminosiloxane (t‐BuO)2Si(OAli‐Bu2)2 ( 7 ) along with Me2SiH2 and Ph2SiH2. |
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Keywords: | Silicon Siloxane Ring structure NMR spectroscopy Crystal structure |
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