Preparation Of The Chiral Intermediate For(+)-Biotin Synthesis And Total Synthesis Of Yohimbane Alkaloid Sempervilam

This thesis contains the following two parts:(1)In the first part,a preparation of the chiral intermediate for(+)-biotin was described:(4R)-2-Phenylthiazolidine-4-carboxylic acid ?-16 was prepared from L-cysteine and benzaldehyde.Esterification of compound ?-16 produced(4R)-methyl-2-phenylt-hiazolidine-4-carboxylate.Then hydantoin ?-67 was obtained via a one-pot reaction of compound 1-103 with triphosgene and benzylamine.The total yield of the three steps is approximately 87%.The method is environmentally friendly,lower cost,and suitable for industrial production.(2)In the second part,we described the total synthesis of ?-carboline alkaloids Sempervilam.Heptanedioic acid dimethyl ester was prepared from heptanediacid by esterification.Then P-carbonyl compound ?-11 was obtained via Dieckmann reaction of heptanedioic acid dimethyl ester with AICl3 and triethylamine.Exposure of compound ?-11 with ethyl cyanoacetate in acetic acid and ammonium acetate furnished compound ?-12.Hydrolysis and decarboxylation produced compound?-13 by refluxing in concentrated hydrochloric acid.Esterification of compound?-13 afforded compound ?-14.Selective hydrolysis of compound ?-14 with potassium carbonate produced compound ?-15.Acylation of tryptamine with ?-15 with DMAP and DCC gave compound ?-16.Cyclization of compound ?-16 with phosphorus oxychloride provided compound ?-17 via Bishler-Napieralski reaction.Then the compound ?-5 was obtained via the reaction of ?-17 with DBU.At last,aromatization of compound ?-5 with cupric bromid afforded desired compound ?-1.The total yield of ten steps is approximately 19%.