Abstract Opiate antagonists stimulate the release of LH and might, therefore, contribute to an innovative therapy for the treatment of numerous clinical syndromes characterized by hypofunction of the HHG axis. The purpose of this work was to design and synthesize pure opiate antagonists useful for this therapy. Me, Et, Pr, and PhCH 2 groups were introduced at the crucial 14β-position of morphines and morphinans via a hetero-Diels-Alder key step ...