CRYSTAL STRUCTURE OF A NEW SPIRO COMPOUND

S. García-Granda¹, C. Alvarez-Rúa¹, J. Barluenga², F. Aznar², S. Barluenga².

¹Departamento de Química Física y Analítica. Facultad de Química. Universidad de Oviedo. Spain.
²Instituto Universitario de Química Organometálica "Enrique Moles". Unidad Asociada al C.S.I.C. Spain

Spirocyclic ring systems are important structural features in natural product synthesis. They are encountered in many different classes of compounds ranging from simple bicyclic systems in the dactyloxenes to very complicated molecules as in polyether antibiotics.

The stereospecific reaction of 2-amino-1,3-butadienes with racemic and enantiomerically pure a,b unsaturated exocyclic chromium carbene complexes has been studied.

When 2-amino-1,3 butadiene 1 was reacted with the exocyclic alkoxychromium carbene complex 2 a new spiro compound 3 was obtained in a good yield.

X-Ray crystallographic analysis of compound 3 has proved that the relationship between the three stereogenic centers was as expected for an exo approach of the diene to the less sterically hindered face of the dienophile [1].

1 2 3

[1] Barluenga, J., Aznar, F., Barluenga, S., García-Granda, S. & Alvarez-Rúa, C. (1997). "Stereospecific [4+2] Reaction between 2-Morpholino-1,3-butadienes and a,b-Unsaturated Exocyclic Chromium Carbene Complexes. Preparation of Enantiomerically Pure Spiro Compounds". SYNLETT, 9, 1040-1042.