Synthesis of a tert-butyl substituted bis(silirane) and comparison with its methyl and phenyl analogs

Crystal structures of three sterically congested disilanes

“…The gauche conformation in 2 appears to be preferred over other conformations when the rotational barrier around the Si-Si bond is high. This trend is observed in the crowded 1,1,2,2-tetraisopropyl-1,2-di-tert-butyldisilane (Pichaandi et al, 2011) and 1,1,2,2-tetra-tert-butyl-1,2-diphenyldisilane (Lerner et al, 2001), which both exhibit a gauche conformation. However, the sterically less hindered 1,1,2,2-tetra-tert-butyl-1,2-dichlorodisilane (Peters et al, 1998) and tetra-tert-butyl-1,2-dihydroxydisilane (West & Pham, 1991) have an anticlinal conformation, similar to 1.…”

“…The study of tetraisopropyl-and tetrakis(2-bromopropan-2yl)-substituted disilanes is of interest due to their importance in the synthesis of bis(silanes), which are precursors for generating transient disilynes (Pichaandi et al, 2011;Kabe et al, 2000;Ando et al, 1997). The synthesis of 1,1,2,2-tetraisopropyl-1,2-di-tert-butyldisilane and 1,1,2,2-tetrakis(2bromopropan-2-yl)-1,2-di-tert-butyldisilane were recently reported by our group (Pichaandi et al, 2011) and the crystal structure of the former determined. However, the structure of the latter could not be solved due to its highly disordered nature, so the exact nature of the influence of the bromine atom in the isopropyl group on the disilane structure could not be determined.…”

“…Disilanes 1 and 2 were prepared according to the literature procedures (Lambert & Urdaneta-Perez, 1978;Pichaandi et al, 2011). Colorless crystals of 1 and 2 were obtained from hexane and dichloromethane solutions, respectively.…”

Flexible synthesis of anthracycline aglycone mimics via domino carbopalladation reactions

“…However, the yields were low in all cases. Changing the bromination reagent to elemental bromine significantly improved the yields (Table 1, entries 4 and 5) [36]. Diethyl ether proved to be important as a solvent, the change to THF led to a total decomposition – most probably due to ring-opening reactions with bromosilanes [37].…”

Palladium and Platinum η2‐Disilyne Complexes Bearing an Isolable Dialkyldisilyne as a Ligand

“…The higher p out orbital in 3 is due to the less-effective p-accepting character of alkyl groups compared to that of trialkylsilyl groups because trialkylsilyl groups adjacent to the p system effectively stabilize the p energy level due to the low-lying s*(Si-C) orbital. [18,19] Although disilyne 3 in the solid state did not decompose in an inert atmosphere at ambient temperature for several months, it isomerizes in solution quantitatively to a diastereomeric mixture of bi(silacyclopropane)s [20] 8 a and 8 b (Scheme 3) in approximately 1:1 ratio within 10 h at ambient temperature. [21,22] Similar C À H insertion was observed in thermal reaction of diaryldisilyne 2.…”