Carbon nanotubes-supported palladium nanoparticles for the Suzuki reaction in supercritical carbon dioxide: A facile method for the synthesis of tetrasubstituted olefins

Abstract

A facile and efficient method for the synthesis of tetrasubstituted olefins in supercritical carbon dioxide was developed by using carbon nanotubes-supported palladium nanoparticles (Pd/CNTs) as the catalyst. Compared with common Pd/C, Pd/CNTs could more effectively catalyze the reaction of dibromo-substituted olefins with boronic acids, affording the corresponding tetrasubstituted olefins with moderate to good yields. This environmentally benign route with an easy-to-handle catalyst provides an appealing alternative to the currently available methods.

Pd(0)‐ S‐propyl‐2‐aminobenzothioate immobilized onto functionalized magnetic nanoporous MCM‐41 as efficient and recyclable nanocatalyst for the Suzuki, Stille and Heck cross coupling reactions

“…Figure shows FT‐IR spectra of (a) Fe 3 O 4 (b) Fe 3 O 4 @MCM‐41 (c) Fe 3 O 4 @MCM‐41@nPr‐SH (d) Fe 3 O 4 @MCM‐41@SPATB and (e) Fe 3 O 4 @MCM‐41@Pd‐SPATB respectively. The FT‐IR spectrum of the Fe 3 O 4 nanoparticles (spectrum a) shows the strong absorptions near 579 and 444 cm ‐1 and 3000–3500 cm ‐1 due to Fe–O and O–H stretching vibrations, for the Fe 3 O 4 @MCM‐41 sample (spectrum b) the peaks at 3445 cm −1 is due to the stretching vibrating absorption of O–H band in the surfaced hydroxyl groups, also three characteristic peaks at 460 cm ‐1 , 958 cm ‐1 and 1081 cm ‐1 corresponded to bending, symmetric stretching and asymmetric stretching, Si‐O–Si vibrations respectively . Immobilization of MPTMS on the surface of Fe 3 O 4 @MCM‐41 was indicated by the appearance of two peaks at 2981 and 2936 cm ‐1 , assigned to the C–H stretching vibrations, also S‐H stretching vibration modes as a weak band that appears at 2450 cm ‐1 (Figure c).…”

1,2-Dihaloalkenes in Metal-Catalyzed Reactions

“…Scheme 20 Synthesis of highly substituted alkenes via Negishi cross-coupling reactions Jiang, Zhang, and Zhou developed an efficient method to obtain various tetrasubstituted alkenes 69 from 1,2-dibromoalkenes (E)-1b via a Suzuki reaction with arylboronic acids in supercritical carbon dioxide (Scheme 21). 25 The reactions were performed with two different palladium catalysts, carbon nanotubes-supported palladium nanoparticles (Pd/CNTs) generally affording better yields.…”

Hybrid materials based on Pd nanoparticles on carbon nanostructures for environmentally benign C–C coupling chemistry

“…The use of s-CO 2 as a reducing agent has been shown to be an environmentally friendly technique to render zerovalent metal particles. [95][96][97][98][99][100] High temperatures and high pressures are needed to reduce the inorganic salts that are the origin of the particles. The curvature of the nanotubes is claimed to be responsible for the final size of the particles (Fig.…”

“…95 The attachment of metallic particles onto the CNT surface facilitates the recovery of the catalyst and also avoids disadvantages such as discontinuous operation. 100 Pt particles deposited onto the CNT surface by this method have shown remarkable efficiency as electrocatalysts in low-temperature fuel cells. 101…”