ISSN:
0268-2605
Keywords:
Silylalkynes
;
Diels-Alder
;
α-pyrone
;
Reactivity
;
Synthesis
;
Bis(silyl)benzenes
;
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Six bis(silyl)acetylenes (XMe2Si—C≡C—SiMe2X) with the following varied silicon substituents X were prepared: 1 (Me, Me); 2 (H, H); 3 (C1, H); 4 (CI, CI); 5 (MeO, H); 6 (MeO, MeO). While 1 and 2 may be prepared by the reaction of dilithio- or bis(bromomagnesium)-acetylide with the appropriate chlorosilane, similar reactions designed to give 3-6 yielded oligomers, XMe2Si—(—C≡C—SiMe2)n—X, 7, X=CI, MeO, as the major products, indicating that the acetylenic functionality on silicon activates the chlorosilane towards nucleophilic substitution. Compounds 3 and 4 were prepared by free radical chlorination of 2. Methanolysis of 3 and 4 gave quantitative yields of 5 and 6 respectively.Compounds 1-6 undergo a Diels-Alder reaction with α-pyrone to produce, after loss of carbon dioxide, bis(silyl)-substituted benzene derivatives. The order of reactivity has been determined to be: 4=6〉3=5〉1〉2, indicating that chloro or alkoxy substituents favor the cycloaddition with 2- pyrone. The adducts formed by compounds 3-6 undergo an unusually facile hydrolysis or elimination to give 1,1,3,3-tetramethyl-1,3-disila-2-oxaindane.
Additional Material:
4 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/aoc.590010605
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