The thesis describes a method for the synthesis of 5- and 6-membered guanidine heterocycles via iodocyclisation of N-Boc-allylguanidine, N-Z-allylguanidine and N-Z-N'- ( dimethylallyl)guanidine. The unstable intermediate products from these reactions were reatTanged in the presence of trifluoroacetic acid to f01m the heterocycles 2-imino-4-iodomethyl-imidazolidine-1-cai-boxylic acid tert-butyl ester, 2-imino-4-iodomethylimidazolidine-1-cai·boxylic acid benzyl ester, ( 5-iodo-4,4-dimethyl-tetrahydro-pyrimidin-2-ylidene )-carbamic acid benzyl ester and (5-iodomethyl-4,4-dimethyl-imidazolidin-2-ylidene)-cai·bamic acid benzyl ester.
Synthetic routes to the previously synthesised catalyst (6R, 6 11R, 2R, 2"R)-6,6"-
dimethy ldispiro[tetrahydropyran-2,2'-(2,3 ,4,6, 7 ,8-hexahydro-lH-pyrimido[ 1,2-a] pyrimidine)-8',2"-tetrahydropyran]-9'-ium tetrafluroborate and the novel chiral non-racemic bicyclic guanidine (4R,8R)-3,8-dibenzyloxy-2,4,5,6,7,8,9, 10-octahydro-3H-5a, 1 0-diaza-1-azonia-heptalene tetrafluoroborate are also detailed. The application of these compounds as phase transfer catalysts in the asymmetric epoxidation of chalcones was investigated leading
to enantiomeric excesses of 85-94% (4 examples).