Cobalt(II)-catalyzed chemoselective synthesis of acetals from aldehydes
作者:Subbarayan Velusamy、T Punniyamurthy
DOI:10.1016/j.tetlet.2004.04.126
日期:2004.6
The acetalization of aldehydes has been studied with methanol, ethanol, and 2-propanol using CoCl2 in high yields under reflux conditions. The reaction is simple, efficient, chemoselective and does not involve any other additive.
A novel PVP-I catalyzed acetalizations/transacetalizations of carbonyl compounds has been developed processing with a mild and easy handling fashion. Different types of Acyclic and cyclic acetals were prepared from carbonyl compounds or their acetals successfully. Further applications of newly developed catalytic combination were testified. This protocol featured with simplicity of operation, mild
The thermally induced synthesis of N-(diethoxyphosphoryl)aldimines
作者:Andrzej Zwierzak、Anna Napieraj
DOI:10.1016/0040-4020(96)00420-6
日期:1996.6
The reaction of diethyl phosphoroamidate (2) with aromatic aldehyde diethyl acetals (1) carried out at 120 – 160°C provides a simple, one-step preparation of N-(diethoxyphosphoryl)aldimines (3a−b). The extension of this reaction to aliphatic aldehyde diethyl acetals failed to give the expected imines.
Reductive Cleavage of the C sp 2C sp 3 Bond of Secondary Benzyl Alcohols: Rhodium Catalysis Directed by N-Containing Groups
作者:Kang Chen、Hu Li、Zhi-Quan Lei、Yang Li、Wen-He Ye、Li-Sheng Zhang、Jian Sun、Zhang-Jie Shi
DOI:10.1002/anie.201204338
日期:2012.9.24
1,1‐Biarylmethanol substrates undergo reductivecleavage of the CCbond in the presence of a cationic RhIII catalyst and H2 (see scheme; DG=directinggroup). Various functional groups are tolerated in the reaction system. Preliminary studies indicate that a five‐membered rhodacycle intermediate, which then converts into a RhIII hydride species for the reduction, is involved in the catalytic cycle.
The nickel-catalyzed reductive coupling of alkynes and imines with Et(2)Zn as a reductant by using electron-rich phosphine ligands has been developed, affording various allylic amines with high yields and excellent chemoselectivities. Chiralinduction was also achieved in this reductive coupling reaction when a nickel catalyst containing a chiral spiro phosphine ligand was used.