New routes to clavine-type ergot alkaloids.: Part 2:: Synthesis of the last, so far not yet synthesized member of the clavine alkaloid family, (±)-cycloclavine

Starting from 4-bromo-Uhle's ketone (2), an alkylation step using ethyl 3-methylamino-propionate followed by intramolecular aldol condensation in two steps, transformation of the ester group into a methyl group, and finally cyclopropanation of the 8,9 double bond, resulted in a six-step total synthesis of (+/-)-cycloclavine (1). (C) 2008 Elsevier Ltd. All rights reserved.