Encapsulation of nano-catalysts in permeable silicone elastomers

A copper nitride nanocube catalyst for highly efficient hydroboration of alkynes

The hydroboration of alkynes with bis(pinacolato)diboron is a useful method for the synthesis of vinyl boronate esters, which are essential intermediates in organic syntheses. Copper catalysts have been used extensively in these reactions. However, previously reported Cu-catalyst systems inevitably require additives and elevated temperatures. Herein, we report, for the first time, a simple and efficient hydroboration of alkynes under additive-free and mild reaction conditions (i.e., at a temperature of 30 °C) using a copper nitride nanocube (Cu₃N NC) catalyst. A wide range of alkynes can be transformed into their corresponding boronate esters. Cu₃N NCs are also applicable in the hydroboration of alkynes with tetrahydroxydiboron to synthesize vinyl boronic acids. Moreover, the Cu₃N NCs were easily separated by simple filtration and could be reused several times without any loss of their original activity. Hence, these highly active and reusable Cu₃N NC catalysts offer an environmentally friendly route for the efficient production of vinyl boronates.

Regio- and Stereoselective Syn-Boronation of Terminal Alkynes Catalyzed by Copper Nanospheres on Graphene Nanosheets

Evenly distributed copper nanospheres on reduced graphene oxide were prepared and showed high heterogeneous catalytic activity in converting varying terminal alkynes into (E)-β-styrene boronate esters. The excellent catalytic performance was achieved through the synergistic catalysis between Cu nanospheres and rGO. This work not only is a supplement for preparing (E)-β-styrene boronate esters but also provides a way for the rational designing of high-performance graphene-based catalysts. Meanwhile, the advancement of graphene-based nanomaterials will be motivated to promote their applications in the development of green catalytic chemistry.

Lithium diisobutyl-tert-butoxyaluminum hydride (LDBBA) catalyzed hydroboration of alkynes and imines with pinacolborane

Lithium diisobutyl-tert-butoxyaluminum hydride (LDBBA) catalyzed hydroboration of alkynes and imines with pinacolborane (HBpin) was demonstrated.

Faster and Greener Chemical Reaction Workup Using Silicone Elastomer-Coated Glass Powders

We have developed a substantially faster and greener technique for routine chemical reaction workups. We use silicone elastomer-coated glass powder ("FastWoRX") as an absorbent to extract organic products from a quenched aqueous reaction mixture. After filtration, FastWoRX powder loaded with organic products can serve as a convenient input for flash chromatographic separations. With this technique, tedious and solvent-consuming liquid-liquid extractions are replaced by a simple filtration. Use of FastWoRX reduces solvent use and the E-factor by up to an order of magnitude compared to traditional liquid-liquid extraction-based workup.