• Wittig salt (see Appendix 1) for the conversion of carbonyl compounds to cyclopropylidene derivatives. For use in the synthesis of the isoquinoline alkaloid (-)-mesembrine, see: J. Org. Chem., 60, 6785 (1995). Greatly improved yields in this type of reaction have been obtained with NaH in THF, in the presence of the phase-transfer catalyst TDA-1 (Tris(3,6-dioxaheptyl)amine, L13544): Tetrahedron Lett., 29, 2531 (1988).