Highly efficient formal synthesis of cephalotaxine, using the Stevens rearrangement--acid lactonization sequence as a key transformation.

Cephalotaxine (1), the major alkaloid isolated from Cephalotaxus species, has attracted considerable attention due to the promising antitumor activity of several of its derivatives and its unique structural features. Herein we describe a highly efficient formal synthesis of 1 employing the [2,3]-Stevens rearrangement-acid lactonization sequence as a key transformation from readily available (3,4-dimethoxyphenyl)acetic acid, methyl prolinate, and allyl bromide.