The present disclosure provides processes for the N-dealkylation of tertiary amines and the use of transition metal catalysts to prepare tertiary N-allyl amine derivatives and secondary amine derivatives thereof. The tertiary amines can be alkaloids and, more particularly, the tertiary amines can be opioids. In specific embodiments, the present disclosure provides methods for use in processes for the synthesis of naloxone and naltrexone from oripavine.