1. Considered as Reagent ans Synthetic methods 68. For part 67 see A. Arrieta, B. Lecea, F.P. Cossío and C. Palomo, J.Org.Chem. (in press). The present work has been supported by Departamento de Investigación del Gobierno Vasco (Eusko Jaurlaritzako Hezkuntza Saila), project X: 86.034 and in part by Universidad del Pais Vasco, project 215-05-44/86. A grant from the Ministerio de Educación y Ciencia to J.M.G. is gratefully acknowledged.
2. A novel synthesis of the carbapen-2-em ring system