Nickel-Catalyzed Addition of C−H Bonds of Terminal Alkynes to 1,3-Dienes and Styrenes

Abstract

The C-H bond of a terminal alkyne adds to a carbon-carbon double bond of 1,3-dienes, styrenes, and norbornene at room temperature in the presence of a nickel catalyst in regio- and stereoselective manners. Reaction of triisopropylsilylacetylene with 1-substituted 1,3-butadiene derivatives afforded hydroalkynylation products via introduction of a hydrogen atom and a triisopropylsilylethynyl group to 4- and 3-positions of the dienes, respectively. Likewise, 1-triisopropylsiloxy-1,3-butadiene, 1,3-pentadiene, 1-cyclohexen-1-yl-1,3-butadiene, and 1,3-cyclohexadiene underwent the hydroalkynylation reaction, giving the corresponding 1,4-enyne derivatives in good yields at room temperature. Reaction of p-substituted styrene with triisopropylsilylacetylene also proceeded in the presence of the nickel catalyst, giving the branched hydroalkynylation products in good yields. Norbornene gave a exo-addition product in good yield under the same reaction conditions.

Gold(I)‐Catalyzed Intermolecular Hydroarylation of Alkenes with Indoles under Thermal and Microwave‐Assisted Conditions

“…This result is consistent with the positively charged transition state in gold(I)-catalyzed alkene functionalization proposed in the literature. [11][12][13] The coupling reaction of deuterium-labeled N-methyl indole 1 m [22] with 4-methoxy- [23][24]…”

Stereoselectivity in the Rhodium‐Catalysed Reductions of Non‐Conjugated Dienes

“…Related reactions with NBE were exo-selective. [7] Hydroamidation, [8] catalytic or stoichiometric hydroboration, [9] asymmetric hydrosilylation, [10] hydroamination with iridium or rhodium, [11] gold, [12] or platinum complexes, [13] C À H addition of terminal alkynes, [14] and catalysed alkyne cycloaddition, [15] and catalytic annulation, [16] of NBE are all exo-selective. Several of these reactions give exo-specific addition with norbornadiene as well.…”

Nickel‐Catalyzed Solvent‐Free Three‐Component Coupling of Aldehyde, Alkyne and Amine

“…[12][13][14] Very recently, use of iron- [24] as well as indium-catalyzed [25] A 3 coupling were reported. To the best of our knowledge, the Ni-catalyzed three-component coupling of aldehyde, alkyne and amine has not been reported so far.…”

“…Meanwhile, the recovery and reuse of Ni-Y were also investigated, and the recovered catalyst exhibited a constant activity for up to 8 consecutive cycles (Table 4). 4 , as catalysts is the simplest and most direct route, [12][13][14]16,21] these nickel sources are difficult to handle because of their high air sensitivity and thermal instability. By contrast, Ni II compounds, which are readily available and are convenient to handle, are more preferred as pre-catalysts from a practical point of view.…”

“…Since the seminal work of Wilke, [11] nickel has been shown to catalyse many transformations associated with alkyne functionalization including the addition of alkynes to 1,3-dienes, [12] styrenes, [13] methylenecyclopropanes, [14] enones, [15] arylcyanation, [16] reductive coupling with aldehydes, [17] hydrothiolation, [18] hydrosilylation, [19] multicomponent coupling, [20] homodimerization [21] and cross-trimerization of alkynes. [22] Several excellent studies on nickelcatalysed transformations including cycloadditions, Negishi cross-coupling, N-arylation of nitrogen nucleophiles, Sarylation of thiols, Heck, Suzuki and Sonogashira couplings are also reported, reflective of the growing interest in nickel catalysis.…”