An unprecedented transfer silylation of alcohols catalyzed by the strong Lewis acid B(C6F5)3 is described. Gaseous Me3SiH is released in situ by B(C6F5)3‐catalyzed decomposition of 3‐trimethylsilylcyclohexa‐1,4‐diene and subsequently reacts with an alcohol in a dehydrogenative Si–O coupling promoted by the same boron catalyst. Benzene and dihydrogen are formed during the reaction, but no salt waste is. This expedient protocol is applicable to several silicon groups, and the preparation of trimethylsilyl ethers presented here is potentially useful for alcohol derivatization prior to GLC analysis.
Fully saturated, aliphatic polymers
containing adamantane moieties
evenly distributed along the polymer backbone are of great interest
due to their exceptional thermal stability, yet more synthetic strategies
toward these polymers would be desirable. Herein, we report for the
first time the synthesis of poly(1,3-adamantylene alkylene)s based
on α,ω-dienes containing bulky 1,3-adamantylene defects
precisely located on every 11th, 17th, 19th, and 21st chain carbon
via acyclic diene metathesis polycondensation. All saturated polymers
revealed excellent thermal stabilities (452–456 °C) that
were significantly higher compared to those of structurally similar
polyolefins with aliphatic or aromatic ring systems in the backbone
of polyethylene (PE). Their crystallinity increases successively from
shorter to longer CH2 chains between the adamantane defects.
The adamantanes were located in the PE crystals distorting the PE
unit cell by the incorporation of the adamantane defect at the kinks
of a terrace arrangement. Precise positioning of structural defects
within the polymeric backbone provides various opportunities to customize
material properties by “defect engineering” in soft
polymeric materials.
The preparation of a chiral derivative of [B(C6F5)4]– in which the fluorine atom in the para position of each of the C6F5 groups is replaced by a 1,1′‐binaphthalen‐2‐yl group is described. The new counteranion was isolated as its lithium, sodium, and trityl salts. The chiral trityl salt was then used as a catalyst in selected counteranion‐directed Diels–Alder reactions and a Mukaiyama aldol addition, but no asymmetric induction was achieved. Application of the chiral trityl salt to the generation of silicon cations by silicon‐to‐carbon hydride transfer from hydrosilanes failed, presumably as a result of the incompatibility of the relatively electron‐rich naphthyl groups in the borate and the cationic silicon electrophiles.
We report mechanistic insights of the bottom-up synthesis of nanodiamonds (NDs) from adamantane derivatives as molecular precursors. Thermal cracking of tetracosane below the decomposition temperature of adamantane, 1-adamantylamine or 2-azaadamantane revealed the initial steps of seeded diamond growth mechanism based on pyrolysis studies.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.