The present invention relates to a process for the hydrogenation of imines with hydrogen in the presence of iridium catalysts. In particular the present invention relates to a process for the hydrogenation of imines with hydrogen under elevated pressure in the presence of an iridium catalysts and with or without an inert solvent, wherein the reaction mixture comprises a phosphonium chloride, bromide or iodide in the presence or in the absence of an acid, which can be an organic or inorganic acid, soluble or insoluble in the reaction mixture. Suitable imines are especially those that contain at least one (Formula I) group. If the groups are substituted asymmetrically and are thus compounds having a prochiral ketimine group, it is possible in the process according to the invention for mixtures of optical isomers or pure optical isomers to be formed if enantioselective or diastereoselective iridium catalysts are used.
31P chemical shifts and31P—−13C coupling effects in the stereochemical analysis of benzo-7-phosphanorbornene derivatives
作者:Louis D. Quin、F. Christian Bernhardt
DOI:10.1002/mrc.1260231110
日期:1985.11
The first phosphines based on the benzo‐7‐phosphanorbornene system have been prepared and found to have extremely deshielded 31P nuclei. The phosphine with a P‐tert‐butyl group gives the most downfield value (δ +152.5) ever recorded for a tertiary phosphine. The lone‐pair orientation in phosphines controls the magnitude of 2J (PC) and 3J (PC), and these effects were used to determine stereochemical