ISSN:
0009-2940
Schlagwort(e):
Silaethene derivatives
;
Furans
;
Cycloaddition reactions
;
Rearrangements
;
Sila heterocycles
;
Diels-Alder reactions
;
Chemistry
;
Inorganic Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
Sila Heterocycles, XXII[1]. - Diels-Alder Reactions of Dichloro(neopentyl)silaethene with Furans and Rearrangement of the Resulting Bicycles into Monocyclic Si - O Seven-Membered Ring compoundsThe reaction of trichloro(vinyl)silane (1) and LitBu (2) initially leads to the α1-lithio adduct Cl3SiCH(Li)CH2tBu (3) which can be trapped by trimethylsilyl triflate yielding the C1-silylated product [Cl3SiCH(SiMe3)CH2tBu (5)]. 1,2-LiCl elimination from 3 gives dichloro(neopentyl)silaethene [Cl2Si=CHCH2tBu (4)] as intermediate. This can be established by insertion of 4 into the Si - O bond of Me3SiOMe to Cl2Si(OMe)CH(SiMe3)CH2tBu (6). 4 is a dienophile of high activity and reacts with the furans 7 - 9 to give the [4 + 2] cycloaddition compounds 10 - 12. These Diels-Alder products are thermally unstable and decompose slowly at room temperature into the starting furans and tetrachlorodisilacyclobutane (15). Under thermolysis conditions (3 d/17°C) they rearrange into the monocyclic Si - O seven-membered ring compounds 16 - 18. A mechanism for the 7-Oxa-2-silabicyclo[2.2.1]hex-5-en → 1-Oxa-2-silacyclohepta-4,6-diene rearrangement is proposed.
Zusätzliches Material:
1 Tab.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/cber.19931260305
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