... Abstract. The total synthesis of 18,19-didehydrotabersonine, 3-OXO-18,19- didehydrovincadifformine,is described. References. 1; G. Costello and JE Saxton, preceding communication. 2; RZ Andriamialisoa, L. Diatta, P. Rasoanaivo, N. Langlois, P. Potier; Tetrahedron, 31 (1975), p. 2347. ... 18; G. Hugel, J. Lévy; J.Org. Chem., 51 (1986), p. 1594. 19; JB Cloke, FJ Pilgrim; J.Am.Chem.Soc., 61 (1939), p. 2667. ...