Highly reactive oligosilyltriflates—synthesis, structure and rearrangement

Abstract

The novel branched oligosilyltriflates of formula [TfO(Me 3 Si) 2 Si] 2 E (2a-d) [E ¼ 0 (2a), SiMe 2 (2b), GeMe 2 (2c), SiMe 2 -SiMe 2 (2d)] and [TfO(Me 3 Si) 2 SiSiMe 2 ] 3 SiMe (9) have been prepared by the protodesilylation of [Ph(Me 3 Si) 2 Si] 2 E (1a-c), [H(Me 3 Si) 2 Si] 2 E (5d) and [Ph(Me 3 Si) 2 SiSiMe 2 ] 3 SiMe (8) using TfOH (CF 3 SO 3 H) as reagent in almost quantitative yields. The crystal structure of 2b is reported.w Electronic supplementary information (ESI) available: experimental details. See

Facile Silylation of Cyclitols Using Silyl Bis(triflates)

“…To raise their reactivity, triflate was used instead of halogens , . These silyl triflates were prepared according to a facile, previously published method reacting phenylsilanes with triflic acid in nearly quantitative yield , . The silylation of diols was achieved in a one pot procedure by preparing the highly reactive silyl triflates from the respective phenyl compound followed by subsequent reaction with diols without further isolation of the triflate…”

Synthesis and Structure of Cyclic Trinuclear Zinc Disiloxides

“…In analogy to the synthesis of the trisilane-1,3-diol 2a previously reported, [5] treatment of Ph(Me 3 Si) 2 Si-K with BrCH 2 CH 2 Br provides easy access to the diphenyl oligosilane 1b in high yields. [6] This compound was treated with two equivalents of trifluoromethanesulfonic acid (TfOH) and subsequently hydrolyzed to give almost quantitatively the silanediol 2b as a colorless solid (Scheme 1). The compound slowly decomposes at room temperature within several days and must be stored in a freezer at ca.…”

Novel Carbohydrate-Based Mono- and Bidentate Oligosilyl Ethers

“…To a stirred solution of 2,4-bis(trimethylsilyl)-1,1,1,3,3,5,5,5-octamethyl-2,4-diphenylpentasilane (3b) 24 (750 mg, 1.34 mmol) in dry CH 2 Cl 2 (30 mL), TfOH (0.26 mL, 2.95 mmol) was added at -20°C and stirring was continued for 1 h. Subsequently, 1,2-O-isopropylidene-a-D-glucofuranose (5) 30 (290 mg, 1.34 mmol) was added and air was bubbled through the solution. The reaction was quenched upon completion (TLC control) with sat.…”

“…In the research group of C. Krempner, efficient synthetic strategies were applied to the preparation of oligosilyl 1,2-, 1,3-and 1,4-bistriflates being potential reagents for the synthesis of carbohydrate-based cyclic silyl ethers with different ring sizes. 24 In the context of our ongoing studies, selected silyl ethers of D-glucofuranose and D-fructopyranose derivatives were investigated with respect to stability and the favoured ring sizes of cyclic oligosilyl ethers. The silylations were carried out with oligosilyl triflates (hypersilyl triflate 2 25 and oligosilyl bis(triflates) 4a-c 24 ) prepared from the appropriate phenyl and hydrido silanes 1 and 3a-c by treatment with triflic acid (Scheme 1).…”

“…13 C NMR (75 MHz, CDCl 3 ): d = 111.9 (i-Pr-C), 105.9 (C-2), 74.3 (C-5), 72.6 (C-4), 72.0 (C-1), 69.7 (C-3), 63.9 (C-6), 26.8, 26.4 (i-Pr-CH 3 ), 0.4 (SiMe 3 ). 29 O-[2,4-Bis(trimethylsilyl)-1,1,1,3,3,5,5,5-octamethylpentasilan-2,4-diyl]-1,2-O-isopropylidene-a-D-glucofuranose (11) To a stirred solution of 2,4-bis(trimethylsilyl)-1,1,1,3,3,5,5,5-octamethyl-2,4-diphenylpentasilane (3b) 24…”