Lithium-silylindolide as precursor of 1,2-, 1,3-bis (silyl)indoles and bis(indole-1,3-yl) silane

Lithium-indolide reacts with difluorosilanes (F2SiR2: R = CHMe2 (1); CMe3 ( 2)) in a molar ratio 2:1 with formation of bis(indole-1-yl) silanes. The 1- (di-tert-butylfluorosilyl) 3-(fluorodiisopropylsilyl)indole (3) is obtained in the reaction 1- (di-tert-butylfluorosilyl) -3-lithium-indolide and F2Si (CHMe2)(2). In st molar ratio 2:1 the bis(1-di-tert-butylfluorosilyl-indole -3-yl)diisopropylsilane 4 is formed. As a byproduct bis(1-di-tertbutymuoros ilyl-indole-3-yl) dimethyhmethane (5) is isolated. A cleavage of THF and th e formation of (indole-1-yl)diisoprppylvinyloxysilan (6) occurs in the reac tion of 1-diisopropylfluorosilylindole with t-BuLi in THE 1-(di-tert-butylf luorosilyl)indole reacts with n-BuLi/TMEDA accompanied by an 1,2-anionic si lyl group migration to give the 2(di-tert-butylfluorosilyl)-1-lithiumindoli de 7. Hydrolysis of 7 gives the 2-(di-tert-butylfluorosilyl)indole (8). In the reaction of 7 with F2Si(CHMe2)(2) the 1-(diisopropylfluorosilyl)-2-(di- tert-butyl- fluorosilyl)indole 9 is obtained. 1-n-Butyl-diisopropylsilyl)in dole (10) is the product of the reaction of F2Si(CHMe2)(2), n-BuLi/TMEDA an d indole at -70 degrees C. Lithium-indolide reacts with 3 to give the 1-(di -tert-butylfluorosilyl)indole-3-yl) (indole-1-yl)-diisopropylsilane (11), t he first example of this class of substances. In the reaction of 1, F2SiMe2 , and t-BuLi in THF the 1-(diisopropyl (indole-1-yl)silyl)-3-dimethyl-(3.3- dimethylbutylsilyl)indole 12 is isolated. The crystal structures of 2, 5 an d 9 are discussed.