The N-dealkylation of levorphanol (I) by means of phenyl chloroformate gave rise to (-)-3-hydroxymorphinan (II). This was then condensed with cyclobutanecarbonyl chloride (III) to afford the diacyl derivative (IV). The reduction of the amide group of (IV), with concomitant ester cleavage, by means of LiAlH4 furnished the desired compound, which was finally isolated as the mandelate salt.