Access to Acyclic Z -Enediynes by Alkyne Trimerization: Cooperative Bimetallic Catalysis Using Air as the Oxidant

Regio- and stereocontrolled synthesis of borylated E-enynes, Z-enediynes and derivatives from alkenyl-1,2-bis-(boronates)

An efficient stereo-controlled synthesis of enyne and enediyne derivatives, via sequential Suzuki-Miyaura coupling reactions from easily prepared 1-alkene-1,2-diboronic esters and alkynyl bromides, is reported. The resulting enyne boronic esters were subjected to Borono-Mannich and Suzuki coupling reactions independently to obtain α,β-unsaturated aminoester and tri-substituted olefin derivatives, respectively. Additionally, divergent syntheses of triazole and cyclopropylboronate derivatives are also reported.

On-surface synthesis of enetriynes

Belonging to the enyne family, enetriynes comprise a distinct electron-rich all-carbon bonding scheme. However, the lack of convenient synthesis protocols limits the associated application potential within, e.g., biochemistry and materials science. Herein we introduce a pathway for highly selective enetriyne formation via tetramerization of terminal alkynes on a Ag(100) surface. Taking advantage of a directing hydroxyl group, we steer molecular assembly and reaction processes on square lattices. Induced by O₂ exposure the terminal alkyne moieties deprotonate and organometallic bis-acetylide dimer arrays evolve. Upon subsequent thermal annealing tetrameric enetriyne-bridged compounds are generated in high yield, readily self-assembling into regular networks. We combine high-resolution scanning probe microscopy, X-ray photoelectron spectroscopy and density functional theory calculations to examine the structural features, bonding characteristics and the underlying reaction mechanism. Our study introduces an integrated strategy for the precise fabrication of functional enetriyne species, thus providing access to a distinct class of highly conjugated π-system compounds.

Copper-catalyzed regio- and stereoselective fluorocarboalkynylation of alkynes

It is attractive to establish an efficient and practical platform affording functional compounds using readily available feedstocks as starting materials under mild conditions.

Rhodium/Silver Synergistic Catalysis in Highly Enantioselective Cycloisomerization/Cross Coupling of Keto-Vinylidenecyclopropanes with Terminal Alkynes

A rhodium/silver synergistic catalysis has been established, enabling cycloisomerization/cross coupling of keto-vinylidenecyclopropanes (VDCPs) with terminal alkynes toward the regio- and enantioselective formation of diversified tetrahydropyridin-3-ol tethered 1,4-enynes in good yields and high ee values. In this synergistic catalysis, Rh(I) and Ag(I) catalysts selectively activate keto-VDCP substrates and terminal alkynes to generate the π-allyl Rh(III) complex of oxa-rhodacyclic intermediate and Ag alkynyl intermediate, respectively. The rapid transmetalation of alkynyl groups from Ag to Rh is proposed to play a key role in realizing the regioselective cleavage of the distal bond of the three-membered ring in this transformation.

One-step synthesis of conjugated enynenitriles from bromocyanoacetylene

Bromocyanoacetylene is able to provide conjugated enynenitriles stereoselectively in one step from alkynes, secondary amines and co-catalysts.