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New ways to synthesize 1,2- and 1,3-bis(silyl)indoles are shown in this paper and new members of these classes of substances are isolated and characterized The crystal structures of the lithium salt of 2-(tert-butyldimethylsilyl) indole (1) (space group P21/c,a = 1018.0(3), b = 1651.4(3), c = 1648.9(5) pm, β = 94.54(3)°, V = 2.763(1) nm3, ρcalc = 1.090 Mg/m3, Z = 4, 4831 reflections, R1 (I > 2σ(I) = 0.052, wR2 (all data) = 0.152) and 1-(di-tert-butylfluorosilyl)-2-(trimethylsilyl)indole(4) (space group P21/c,a = 1015.5(1), b = 1733.5(3), c = 1261.3(2)pm, β = 105.61(2)°, V = 2.1385(5) nm3, ρcalc = 1.086 Mg/m3, Z = 4, 2779 reflections, R1 (I > 2σ(I) = 0.055, wR2 (all data) = 0.163) are reported. Furthermore the first examples of bis(indol-3-yl)silanes (9, 10) are isolated. Specific reactions for the desilylation of 1, 3-bis(silyl)indoles are discussed.

Di-tert-butylmethylsilylamide reacts with n-BuLi to give the tetrameric lithium di-tert-butylmethylsilylamide 1. Reactions of lithium (di-tert-butylmethylsilyl)amide 1 with SiF4 give the mono- (2), bis- (3), tris- (4), and tetrakis- (5) -[(di-tert-butylmethylsilyl)amino]silanes. Lithiated 3 reacts with Me3SiCl to form (di-tert-butylmethylsilyl-trimethylsilyl)amino-(di-tert-butylmethylsilyl)amino-difluorosilane (6); the 1,3-diaza-2,4-disilacyclobutane 7 is obtained by LiF elimination. The lithium derivative of 6 (compound 8) crystallizes with formation of a (SiFNLi) four-membered ring system. The 19F-NMR spectrum proves that the Li–F bond fluctuates in solution. Reactions of 1 with (Me3Si)2C(SiF3)2 afford different products (9, 10) by controlling the reaction sequence. An excess of 1 reacts to give a four-membered CSi2N ring system, the 1-(di-tert-butylmethylsilyl)-2,4-bis-[(di-tert-butylmethylsilyl)-amino]-2,4-difluoro-3-bis(trimethylsilyl)-1-aza-2,4-disila-cyclobutane (9), disubstitution with formation of bis[(di-tert-butylmethylsilyl)aminodifluorosilyl]bis(trimethylsilyl)methane (10) occurs in a molar ratio of 2:1. The cyclodisilazane 11 is obtained from dilithiated 10 in an intramolecular interconversion reaction. The crystal structures of 1, 8, 9, and 11 are reported.

Di-tert-butyldichlorosilane yields with methylamine (CMe3)2Si(NHMe)2, 1. The dilithium-derivative of 1 (2) reacts with PF3 to give the cyclodiphosph(III)azane, [(CMe3)2SiFNMe[sbnd]P[sbnd]NMe]2, 3. The dithiocyclodiphosph(V)azane; [(CMe3)2SiFNMe[sbnd]SP[sbnd]NMe], 4 is formed by treatment of 3 with sulfur. Reaction mechanisms and crystal structures are discussed. Di-tert-butyldichlorsilan bildet mit Methylamin (CMe3)2Si(NHMe)2 1. Das Dilithiumderivat von 1 (2) reagiert mit PF3 unter Bildung des Cyclodiphosph(III)azans, [(CMe3)2SiFNMe[sbnd]P[sbnd]NMe]2, 3. Das Dithiocyclodiphosph(V)azan, [(CMe3)2SiFNMe[sbnd]SP[sbnd]NMe]2 4 entsteht in der Reaktion von 3 mit Schwefel. Die Reaktionsmechanismen und Kristallstrukturen werden diskutiert.

Four-membered heterocycles (2, 3, 4, 5, 7) are formed in [2 + 2]-cycloadditions of the SiN double bond of di-tert-butyl(di-tertbutylphenylsilyl)iminosilane (1) with compounds including PN (2), CC (3), C0 (4, 5), and CN (7) double bonds. For example: di-tert-butyl(di-tert-butylphenylsilyl)iminosilane (1) reacts with bis(trimethylsilyl)amino-(trimethylsilyl)iminophosphane under formation of the 1,3-diaza-2-phospha-4-silacyclobutane (2). The 1-aza-2-silacyclobutane (3) is obtained in the reaction of the iminosilane (1) with ethylvinylether. Treatment of 1 with 2-methylpropenal leads to the formation of the 1-aza-3-oxa-4-silacyclobutane (4). The 1-aza-3-silacyclobutane (5) is formed in the reaction of the iminosilane 1 and tert-butylisocyanate. A 1,3-silylgroup migration from the nitrogen to the oxygen occurs in the reaction of 1 with trimethylsilylisocyanate. The aminonitril (6) is obtained. The 1,3-diaza-4silacyclobutanone (7) is the product of the reaction of 1 and phenylisocyanate. The crystal structures of 2, 3 and 7 are reported.