Disclosed is a process for the preparation of phosphine-aminophosphines that are useful in the formation of catalysts useful in carrying out a wide variety of reactions such as asymmetric hydrogenations, asymmetric reductions, asymmetric hydroborations, asymmetric olefin isomerizations, asymmetric hydrosilations, asymmetric allylations, asymmetric conjugate additions, and asymmetric organometallic additions. The process comprises the steps of (1) contacting a compound of formula 2
R
2
P—L—NHR
3
2
with phosphorus trihalide PX
3
in the presence of an inert, organic solvent and an acid acceptor to produce intermediate compound having formula 3
(2) contacting intermediate compound 3 with a reactant having the formula R
1
—M
1
, R
2
—M
1
or a mixture thereof.
Process for the preparation of n-acetylphenylalanine
申请人:Hoechst Aktiengesellschaft
公开号:US04892971A1
公开(公告)日:1990-01-09
In the process for the preparation of N-acetylphenylalanine by opening the ring of 2-methyl-4-benzylidene-1,3-oxazolin-5-one with water to give 2-acetaminocinnamic acid and subsequently catalytically hydrogenating the latter, both reaction stages are carried out in a mixture of an aliphatic C.sub.3 -ketone to C.sub.10 -ketone or a water-miscible ether and water as the solvent, and the hydrogenation of the 2-acetaminocinnamic acid is carried out at temperatures of 10.degree. to 50.degree. C. and pressures of 1 to 15 bar in the presence of a supported palladium catalyst.