An anion controlled stereodivergent semi‐hydrogenation of alkynes is reported. The reactions are catalyzed by the low‐cost and stable nickel(II) salts, using water as environmental friendly hydrogen source with zinc powder as metal reductant. Interestingly, the stereoselectivity of the reaction is well controlled by the anion of the nickel(II) salt. The present methodology allowed a low‐cost and convenient preparation of trans‐ and cis‐alkenes under mild conditions. The reaction mechanism is proposed with water as the hydrogen donor on the basis of the control experiments.
A facile and cost-effective
method for the preparation of fluoroalkylated
compounds has been described by the direct photoexcitation of halofluoroalkanes
with blue light absorptivity, enabling the difluoroalkylation of aryl
ketones. The methodology has provided an efficient, mild, and catalyst-free
synthetic method for quaternary difluoroalkylated arenes and tetrasubstituted
monofluoroalkenes.
An
efficient, catalyst/photocatalyst-free, and cost-effective methodology
for the decarboxylative alkylation of α,β-unsaturated carboxylic acids to synthesize β,γ-unsaturated nitriles has
been developed. The reaction proceeded in an environmentally benign
atmosphere of blue light-emitting diode irradiation with K2CO3 and water at room temperature. The methodology worked
for a wide range of substrates (22 examples) with up to 83% yield.
The protocol is also compatible for gram-scale synthesis.
A palladium‐catalyzed asymmetric hydrogenation of levulinic acid has been successful developed by using Zn(OTf)2 as co‐catalyst. The present method not only has provided a strategy in the palladium‐catalyzed asymmetric hydrogenation of ketone, but also allowed the preparation of a wide range of chiral γ‐valerolactones in good yields with excellent enantioselectivities.
Comprehensive Summary
New blue‐light promoted methods for the addition of iodoacetonitrile (ICH2CN) to alkene/alkynes have been developed. The reaction led to the formation of cyanoalkylated products when conjugated alkene/styrene was used. In the case of alkynes and non‐conjugated alkenes, iodoalkylation takes place furnishing the corresponding alkenyl iodides and alkyl iodides, respectively. Notably, trans‐alkenyl iodides were obtained as the major product. A plausible reaction mechanism is also proposed.
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