Regio‐ and Stereoselective Dimerization of Arylacetylenes and Optical and Electrochemical Studies of (E)‐1,3‐Enynes

Abstract

dihydroimidazol-2-ylidene) promotes regio-and stereospecific dimerization of a variety of arylalkynes to give (E)-1,3enynes in good to excellent yields. An efficient and practical procedure for their synthesis was developed using a biphasic aqueous alkali/heptane system. Optical and electronic properties of (E)-1,3-enynes are highly tunable. Depending on the nature of the substituents, HOMO energies vary in the range 5.3-6.0 eV. (E)-1,3-Enynes can exhibit intense photoluminescence in the spectral region 350-500 nm.

Efficient Multigram Approach to Acetylenes and CF3‐ynones Starting from Dichloroalkenes Prepared by Catalytic Olefination Reaction (COR)

“…1 H NMR (400.1 MHz, CDCl 3 ): δ 3.09 (s, 1H, C≡C H ), 7.29 (d, 2H, Ar, 3 J HH = 8.4 Hz), 7.41 (d, 2H, Ar, 3 J HH = 8.4 Hz). 1 H NMR data of 7a are in agreement with those in the literature …”

Computational insight into the mechanism of the Pd(0)–Brønsted acid cooperatively catalysed head-to-tail dimerization of terminal alkynes

“…20 In addition, Nechaev and co-workers introduced the selective head-to-head dimerization promoted by NHC-Pd(II) complexes, such as (SIPr)Pd(cinnamyl)Cl, in a biphasic aqueous alkali/heptane system. 21 The Pd-catalysed head-to-head dimerization in water was reported by Nájera and co-workers. 22 An in-depth understanding of the mechanisms of the selective dimerization of terminal alkynes is essential to design more efficient transformation.…”

Polymerization of 5-Alkylidene-2-norbornenes with Highly Active Pd–N-Heterocyclic Carbene Complex Catalysts: Catalyst Structure–Activity Relationships

“…A promising combination of catalytic activity, durability, and good tolerance to the functional groups was found in Pd catalysts. At the same time, it is well known that the introduction of an N-heterocyclic carbene (NHC) ligand into transition metal complexes leads to higher stability and improved catalytic properties. , Different Pd complexes with NHC ligands were developed as catalysts for cross-coupling reactions like C–C − and C–N bond − formation and others, , but their catalytic activity in the polymerization of alkenes is less known. It seems attractive to use Pd complexes bearing NHC ligands as (pre)­catalysts for the addition polymerization of norbornene derivatives.…”