Inova 300 spectrometer

All synthetic steps were performed under inert conditions using standard Schlenk techniques. Solvents were dried with a column purification system.^{17 (link)} Commercial tetrachlorogermane (GeCl₄), tert-butyllithium (t-BuLi), mesitylbromide (MesBr), chloro(trimethyl)silane (SiMe₃Cl), and KOtBu were used without further purification. The used acid fluorides were produced according to the corresponding literature.^{18 1}H (299.95 MHz) and ¹³C (75.43 MHz) NMR spectra were recorded with a Varian INOVA 300 spectrometer in CDCl₃ or C₆D₆ solution and were referenced versus TMS by using the internal ²H lock signal of the solvent. UV-Vis spectra were recorded with an Agilent Cary 60 UV-Vis spectrometer. Mass spectra were acquired with a Q-TOF Premier from Waters, Manchester, England. The original ESI source of the instrument was replaced by a standard LIFDI source from Linden CMS, Weyhe, Germany. IR spectra were recorded with a Brucker ALPHA. Melting points were determined by a Stuart automatic melting point (SMP50).

All reactions involving air-sensitive
compounds were carried out under an atmosphere of dry nitrogen or
argon using either Schlenk techniques or a glove box. All solvents
were dried using a column-based solvent purification system.^{44 (link)} 2,2,5,5-Tetrakis(trimethylsilyl)decamethylhexasilane,^{45 (link)} 1,4-dipotassio-1,1,4,4-tetrakis(trimethylsilyl)tetramethyltetrasilane
(1),^{36 (link)} 1,3-bis[potassiobis(trimethylsilyl)silyl]-1,1,3,3-tetramethyldisiloxane
(3),^{41 (link)} Cp₂YCl,^{46 (link)} 1,1′-bis[tris(trimethylsilyl)silyl]ferrocene,^{42 (link)} and 5(42 (link)) were prepared following published procedures. All other chemicals
were obtained from different suppliers and used without further purification.
¹H (300 MHz), ¹³C (75.4 MHz), and ²⁹Si (59.3 MHz) NMR spectra were recorded on a Varian INOVA 300 spectrometer.
If not noted otherwise all samples were measured in C₆D₆. To compensate for the low isotopic abundance of ²⁹Si, the INEPT pulse sequence was used for the amplification of the
signal.^{47 (link)−49 (link)} Spectra are calibrated to the deuterium resonance
of the solvent (C₆D₆)^{50 (link)} and referenced to tetramethysilane (TMS).^{51 (link)}Elementary analyses were carried out using a Heraeus VARIO
ELEMENTAR.

All reactions were performed in Mettler-Toledo Easymax 102 Advanced Synthesis Workstation using 25 mL reactor tubes. NMR spectra were recorded on Varian Inova 300 spectrometer (300 MHz ¹H, 75 MHz ¹³C, 285 MHz ¹⁹F) at 25 °C. ¹H-NMR spectra were obtained as solutions in CDCl₃ with TMS as the internal standard. ¹⁹F-NMR spectra were obtained as solutions in CDCl₃ with CFCl₃ as the internal standard. N-bromosuccinimide was freshly recrystallized before use. All other chemicals used for synthetic procedures were obtained from commercial sources and were of reagent grade purity or better (Merck, Sigma Aldrich, Carlo Erba, Fluka, Fisher Scientific, Apollo Scientific, etc.). Reactions were monitored by TLC with silica gel coated plates Silica gel/TLC cards, DC-Alufolien-Kieselgel with 60 Å medium pore diameter (Sigma Aldrich) and detection was conducted by UV absorption (254 nm). Purification of certain products was conducted on preparative silica gel glass plates PLC Kieselgel 60 F254 with 2 mm layer thickness. Succinimide, isolated at the end of the reaction, can easily be recycled back to N-bromosuccinimide according to the standard procedure by NaOH, as elaborated in other reports [56 (link)]. Copies of ¹H-NMR, ¹³C-NMR and ¹⁹F-NMR spectra of isolated final products are available in Supplementary material file online.

All experiments were performed
under a nitrogen atmosphere using standard Schlenk or glove-box techniques.
Solvents were dried using a column solvent purification system.^{57 (link)} Commercial KOtBu (97%) was dissolved in THF
and filtered under a nitrogen atmosphere to remove potassium hydroxide
and dried by heating to 150 °C in vacuo for 2 h after removal
of the solvent prior to use. Otherwise commercially available chemicals
were used as purchased. Compound 1 was synthesized according
to published procedures.^{13 (link)1}H (299.95 MHz), ¹³C (75.43 MHz), and ²⁹Si (59.59
MHz) NMR spectra were recorded on a Varian INOVA 300 spectrometer,
using either the internal ²H-lock signal of the solvent
or a D₂O capillary as an external lock. Chemical shift
values are referenced versus TMS. High-resolution mass spectrometry
(HRMS) spectra were recorded on a Kratos Profile mass spectrometer
equipped with a solid probe inlet. Melting points were determined
in one-side melted off capillaries using a Buechi 535 apparatus and
are uncorrected. Elemental analyses were carried out using a Hanau
Vario Elementar EL apparatus.