REACTION OF COMPLEX LIGANDS .40. SYNTHESIS OF NITROGEN-HETEROCYCLES BY DIASTEREOSELECTIVE INTRAMOLECULAR AMINOCARBENE ANNELATION

Simply heating the carbene complexes 1 in toluene converts them diastereoselectively in 50% yield into the nitrogen‐containing tricyclic compounds 2. Whereas the relative configuration of the C atoms with respect to the substituent R and the Cr(CO)3 fragment is established by the metal‐induced annelation. the formation of the stereocenter at the point of linkage of the two five‐membered rings may be explained by a subsequent, thermodynamically controlled enamine‐imine tautomerization step. R = Me, Et, SiMe3. (Figure Presented.) Copyright © 1990 by VCH Verlagsgesellschaft mbH, Germany