| The chiral hydantoin compound have shown excellent bioactivity,which were widely used in the area of pharmaceuticals food and agrochemicals. Currently the chiral hydantoin derivatives were mainly prepared by stereospecific synthesis or chiral resolution. Enantioselective hydrogenation of hydantoin derived exocyclic alkenes is one of the most ideal method to get these compounds. However, successful examples are rare. This project will focus on the development of highly effective and practical asymmetric hydrogenation of hydantoin derived exocyclic alkenes with wide substrate scope by using chiral phosphine complexes as catalysts. The main research work was outlined follows:1. The hydantoin derived exocyclic alkenes were synthesiszed by using aromatic aldehydes. The structure was characterized by GC-MS, 1H NMR,13 C NMR. The reaction condition were systematically studied. The optimized condition was: Aromatic aldehydes(0.05 mo L),Hydantoin(0.05 mo L), 50 m L solvent(ethanol/water = 1/1), ethanolamine(0.03 mo L), 75 ℃, 12 h. The yield was up to 94% with high Z/E selective.A series of substrates 5-(2-methoxybenzylidene)imidazolidine-2,4-dione,5-(4-methoxybenzylidene)imidazolidine-2,4-dione,5-(4-bromobenzyliden e)imidazolidine-2,4-dione,5-(4-chlorobenzylidene)imidazolidline-2,4-dio ne,5-(3-chlorobenzylidene)imidazolidine-2,4-dione,5-(2-chlorobenzylidene)imidazolidine-2,4-dione,5-(2-methylbenzylidene)imidazolidine-2,4-di one,5-(2-ethoxybenzylidene)imidazolidine-2,4-dione,5-(2-butoxybenzyli dene)imidazolidine-2,4-dione were synthesiszed with high yield and Z/E seclectivityt.2. The asymmetric hydrogenation conditions was studied by using5-benzylidene as model. The optimized condition was: 0.5 mmol sub.,S/C = 50, 1.5 mg additives 3, 20 atm hydrogen pressure, 75 ℃, 24 h. The substrates scope was screened on the optimized condition. Up to 99%concersion and up to 99% ee was achived. Specifacally, the synthesis of5-(4-methoxybenzyl)imidazolidine-2,4-dione,5-(2-methobenzyl)imidazoli dine-2,4-dione,5-(4-bromobenzyl)imidazolidine-2,4-dione,5-(4-chloroben zyl)imidazolidine-2,4-dione,5-(3-chlorobenzyl)imidazolidine-2,4-dione,5-(2-chlorobenzyl)imidazolidine-2,4-dione,5-(2-methylbenzyl)imidazolidi ne-2,4-dione,5-(2-ethoxybenzyl)imidazolidine-2,4-dione,5-(2-butoxybenz yl)imidazolidine-2,4-dione were achieved with yield 88%, 89%, 91%,92%, 87%, 86%, 84%, 87%, 88% respectively. Ee values were 87.7%,63.4%, 21.3%, 25.8%, 53.4%, 50.5%, 90.0%, 56.3%, 61.0% respectively. |
