Reductive alkylation of active methylene compounds with carbonyl derivatives, calcium hydride and a heterogeneous catalyst

Selective reduction of nitroarenes using Ru/C and CaH2

Herein, we report an efficient and highly selective method for the reduction of aromatic, heteroaromatic and halonitro compounds using the readily available and cost-effective Ru/C as a catalyst along with unconventional CaH₂ as a source of hydride. In most cases the corresponding anilines can be obtained by simple filtration without further purification. The use of 2-MeTHF and the simple operational work-up constitute a valid alternative to previous methodologies.

Intramolecular Phosphine-Promoted Knoevenagel Based Redox-Reaction

A Knoevenagel based redox-reaction promoted by intramolecular phosphine sources is presented for the first time. The influence of different diketones, aldehydes, bases and acids was investigated. The effects of different substituents were evaluated based on their electronical influence on the diketone structure. With the obtained results a mechanism is proposed, giving information about transition states formed during the reaction, which can lead to different products. This type of an internal redox transformation with a phosphine oxide moiety remaining in the molecule after the redox reaction represents a new type of reaction.

Reductive Knoevenagel Condensation with the Zn–AcOH System

An efficient gram-scale one-pot approach to 2-substituted malonates and related structures is developed, starting from commercially available aldehydes and active methylene compounds. The technique combines Knoevenagel condensation with the reduction of the C=C bond in the resulting activated alkenes with the Zn–AcOH system. The relative ease with which the C=C bond reduction occurs can be traced to the accepting abilities of the substituents in the intermediate arylidene malonates.

Facile and practical hydrodehalogenations of organic halides enabled by calcium hydride and palladium chloride

For the first time, calcium hydride and palladium chloride were used to reduce a wide range of organic halides including aromatic bromides, aromatic chlorides, aromatic triflates, aliphatic bromides, aliphatic chlorides and trihalomethyl compounds.

Formal reductive addition of acetonitrile to aldehydes and ketones

An efficient and highly productive rhodium-catalyzed method for the synthesis of nitriles employing aldehydes or ketones, methyl cyanoacetate, water and carbon monoxide as starting materials has been developed. Simple rhodium chloride without any ligands can be used. The fine tuning of the substrate can lead to the activity higher than 5000 TON.

A new red fluorophore with aggregation enhanced emission by an unexpected “One-step” protocol

In this work, a triphenylamine-benzothiadiazole-based new fluorophore is obtained from a facile “one-step” protocol. A possible reduction mechanism is proposed, and an amine containing α-H plays a key role in the reduction reaction. The resultant product A1H2 exhibits bright red emission in solid state, with an absolute quantum yield of 44.5%. Aggregation induced emission enhancement of A1H2 is also observed with the increased water fraction in THF-H₂O mixture. The nanoparticles of A1H2 reveal good stability and biocompatibility, which are successfully applied in cellular cytoplasm imaging.

Compound A1H2 was synthesized via the reductive Knoevenagel alkylation, whose nanoparticles exhibit bright red emission in aqueous solution.

A base promoted one pot solvent free version of the Ramachary reductive coupling/alkylation reaction for the synthesis of 2,2-disubstituted ethyl cyanoacetates

An N,N-diisopropylethylamine promoted solvent-free Ramachary reductive coupling/alkylation (RRC/A) reaction for the synthesis of 2,2-disubstituted ethyl cyanoacetates has been developed. A series of 2,2-disubstituted ethyl cyanoacetates were synthesized in one pot by the RRC/A reaction of commercially available aldehydes, ethyl cyanacetates, alkyl halides and Hantzsch ester. A solvent free two step multicomponent reaction has also been developed for the preparation of 2,2-dialkylated malononitriles and 2,2-dialkylated 4-nitrophenyl acetonitriles. All the designed RRC/A products could be easily obtained with good yields by these methods.

An N,N-diisopropylethylamine promoted solvent-free Ramachary reductive coupling/alkylation (RRC/A) reaction for the synthesis of 2,2-disubstituted ethyl cyanoacetates has been developed.