Diethylzinc With Aromatic Aldehydes Catalyzed Asymmetric Addition Reaction Of Hydroxy-oxazoline And Tamsulosin Synthesis Of,

The dissertation consists of two parts. One is asymmetric addition of diethylzinc to aromatic aldehydes in the presence of hydroxymethyl oxazoline ligands, The other is study on synthesis of tamsulosin.We use the cheap available L- or D-mandelic acids as our preliminary materials. After protection of hydroxyl group with acetyl chloride by esterification, the esters were treated with L-alaninol (a), D-phenylglycinol (b) et al. in chlorobenzene under reflux to obtain correspondingly 4-mehtyl-4,5-dihydrooxazol-2-yl)(phenyl) methyl acetate IIa in 86.3% yield . The other acetates (IIb-IIg) could beachieved with high yields using the same method. Deprotection of acetyl under condition of 20% sodium hydroxide to afford 4-methyl-4,5-di hydrooxazol-2yl)(phenyl) methanol Ia in 80% yield, 4-isobutyl-4,5-dihydrooxazol-2-yl) (phenyl) methanol Ib in 90% yield. Hydroxymethyl oxazolines Ic-Ig are also obtained in high yield. The seven chiral ligands Ia-Ig were used in catalytic asymmetric addition of diethylzinc to benzaldehydes. Among these oxazolines, the catalyst phenyl (4-phenyl-4,5-dihydrooxazol-2-yl)methanol Ic showed good catalytic effectiveness and achieved 51% enantiomeric excess, 4-tert-butyl-4,5 -dihydromethyloxazol-2-yl)(phenyl)methanol If obtained the best enantiomeric excess (up to 66%). Alkylation of other aromatic aldehydes were investigated with 10% mol If as catalyst. It is seen that this compound is fairly effective with respect to both para-and ortho-substituted benzaldehydes, as well as to cinnamaldehyde and 2-naphthaldehyde. The presence of electron-donor substitutents and bulky substituents in the ortho position appreciably reduces the enantioselectivity, whereas electron-withdrawing groups increase ee value. The best result was obtained in the reaction with...