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Novel N -methylated valine-thiazole cyclic octa- and dodecapeptides are produced by cyclooligomerisation of a N -methylated- l -valine thiazole amino acid HCl in the presence of pentafluorophenyl diphenylphosphinate (FDPP).

Novel proline–thiazole based cyclopeptides were produced by cyclooligomerisation of an L-proline thiazole amino acid HCl in the presence of pentafluorophenyl diphenylphosphinate (FDPP) or diphenyl phosphorazidate (DPPA).

Methods are discussed for the stereoselective synthesis of the (R)-and (S)-enantiomers of the diosphenols ( 5 )–( 8 ) by utilizing the commercially available stereoisomers ( 9 ), ( 12 ), ( 23 ) and ( 25 ) of carvone and limonene, respectively, as chiral starting materials.

Syntheses of diosphenol (3), ψ-diosphenol (4), 6-hydroxydiosphenol (5) and 6-hydroxy-ψ-diosphenol (6), which are constituents of the essential oil from Barosma betulina Bartl. (mountain buchu), are discussed.