Regioselective and enantiospecific synthesis of 6-substituted and 5,6-disubstituted hexahydropyrimidines

Article abstract of DOI:10.1016/S0040-4039(00)74861-1

The preference for 5- over 6-membered rings in the intramolecular cyclisation of amines with diesters can be partially overcome with mixed methyl (or benzyl), tert-butyl diesters, and this effect is enhanced where there is a β-substituent. The hexahydropy