REACTION OF ETHYL N-CYANOMETHYLBENZEHECARBOXIMIDATE WITH ALIPHATIC ALDEHYDES UNDER THE SOLID-LIQUID PHASE TRANSFER CATALYSIS

Ethyl N-cyanomethytbenzenecarboximidate reacted with aliphatic aldehydes under the solid-liquid PTC condition to gire a-ethoxyphenylmethylene- aminoacrylonitrile derivatives and oxazoline derivatives.It is a convenient and new method for synthesis of β,β'-dihyroxy-a-amino acids by hydrolysis of the oxazoline derivatives.

Cyclotrimerization of Aliphatic Aldehydes Catalyzed by Ionic Liquids

Aliphatic aldehydes such as ethanal, propanal, n-butanal, isobutyraldehyde, n-valeraldehyde, isovaleraldehyde, n-hexanal and n-octanal were converted into the corresponding 2.4,6-trialkyl-1,3,5-trioxanes through cyclotrimerization in the presence of the ferric chloride based ionic liquids at room temperature without solvent in high selectivity. The effects of different ionic liquids, acidity of ionic liquids and temperature on cyclotrimerization were also studied. The results showed that the ferric chloride based ionic liquids （apparent molar fraction of FeCl3 （x（FeCl3）= 0.62）） were a kind of efficient catalysts for the cyclotrimerization of aliphatic aldehyde which could be separated conveniently from the reaction mixture and recycled without loss of catalytic activity. The conversion of isobutyraldehyde and the selectivity to 2,4,6-triisopropyl-1,3,5-trioxane were 91.1% and 99.8% respectively under optimum reaction condition （isobutyraldehyde 25.0 g, [Et3NH]Cl/FeCl3 （x（FeCl3）=0.62） 1.0 g, 25 ℃ for 1 h）.

A Novel Synthetic Method for the Preparation of Aliphatic Aldehydes from the Corresponding Carboxylic Acids

A novel synthetic method for the preparation of aliphatic aldehydes from the corresponding carboxylic acids via 1,3-dimethylbenzimidazolium salts is provided. 1,3-Dimethylbenzimidazolium salts were rapidly reduced with sodium/ethanol and then hydrolyzed with hydrochloric acid to obtain aliphatic aldehydes, in which the 1,3-dimethylbenzimidazolium salts can be readily achieved from the corresponding carboxylic acids. The mechanism for the reductive reaction of 1,3-dimethylbenzimidazolium salts with sodium/ethanol was discussed.

Ligand enabled none-oxidative decarbonylation of aliphatic aldehydes

Decarbonylation of aldehydes is a basic organic transformation, which has been developed for more than six-decade. However, as comparing to well-studied aromatic aldehydes, fewer examples for catalytic decarbonylation of aliphatic aldehydes were reported, mainly on simple or special substrates.For α-bulky or highly functionalized ones, stoichiometric Rh(I) were usually required for decent yields.Herein, we present a rare example of Ir(I)-catalyzed direct decarbonylation of α-quaternary aldehydes with broad substrate scope and good functional group compatibility via judicious selection of ligand. Theα-chirality is memorized in this decarbonylation process. In addition, we report a broad-spectrum decarbonylation of α-secondary and α-tertiary aldehydes containing multifunctional groups with an improved Rh(I)/DPPP recipe. Finally, we realized selective decarbonylation of α-tertiary aldehydes in the presence of α-quaternary one via the reactivity differences.

Supramolecular interaction controlled and calix[4]arene ligand assisted Pd-catalyzed C(sp3)-H arylation of aliphatic aldehydes

A calix[4]arene ligand assisted directβ-C-H arylation of tertiary aliphatic aldehydes has been developed via a Pd-catalyzed C(sp3)-H functionalization process.This strategy exhibited good functional group compatibility and C-H bond site-selectivity.Mechanism studies have shown that both synergistic effect and cationic-πsupramolecular interaction between calixarene cavity and transition-metal catalytic center may play an important role in this catalytic cycle.This complementary method would be used in organic and medical chemistry due to the importance of tertiary aliphatic aldehydes.

Visible-light induced transition-metal and photosensitizer-free conversion of aldehydes to acyl fluorides under mild conditions

Acyl fluorides are powerful synthons for acylation with wide application in the synthesis of valued compounds,especially peptides.Herein,a practical and catalyst-free method for the synthesis of acyl fluorides from aldehydes via C(sp^(2))-H fluorination is reported.This method enables the conversion of both aliphatic and aromatic aldehydes into acyl fluorides in good to excellent yields by visible-light under mild conditions in the absence of transition-metal and external photosensitizer.A variety of functional groups were well tolerated for this transformation.This green method provides a practical pathway to synthesize acyl fluorides under mild conditions.