... 5. Malavaud, C, Boisdon, MT, Charbonnel, Y. and Barrans, J. (1979) Tetrahedron Letters, 447-450. 6. Pilgram, K. and Krote, K. (1963) Tetrahedron, 19, 137-141 have described a ... However, Malavaud et al (5) by mass spectrometric analysis showed that the compound was a ...