A full account of the total synthesis of two monoterpene alkaloids, (−)-plectrodorine [(−)-1] and (+)-oxerine [(+)-3], is presented. The key steps involved are the formation of the oxazole alcohol 10 from the γ-butyrolactone 9 and the intramolecular Diels–Alder reaction of the oxazole–olefins 13a, b. Since the sign of specific rotation for the synthetic (+)-3 was different from that reported for natural oxerine, the absolute configuration of this alkaloid is not yet fully understood.