DICHOTOMY OF ENAMINES AT THE C-C BOND OF A (1-ALKYNYL)CARBENE TUNGSTEN COMPLEX - (1-AZONIABUTADIEN-4-YL)CARBONYLMETALATES (-OC)(5)WC(OET)=(CRC)-C-1(=N-AMINOETHENYL)CARBENE COMPLEXES (OC)(5)W=C(OET)CR1=C(NR2)ME(R2)ME, STABLE TORSION ISOMERS OF (2)

Addition of tertiary open-chain enamines (RHC)-H-1=C(NR2)Me 7a-e [NR2 = pyrrolidine, N(i-Bu)(2); R-1 = Ph, CO2Me, CO2Et, CO(2)Bz, CO2-t-Bu] to the 1-alkynylcarbene complex (CO)(5)W=C(OEt)C=CPh (1a) affords nove l (1-azoniabutadien-4-yl)carbonylmetalates (-OC)(5)WC(OEt)=C[C(=N+R2)M e]C(Ph)=CHR1 (2E)-torquo-8a-f by dichotomy of the C=C(N) bond of 8 at the C=C bond of 1. Compounds (2E)-torquo-8 are stable in solid state b ut undergo (2E/2Z) isomerization in solution to give compounds (2Z)-to rquo-8. X-ray structure analyses are reported of compounds (2E)-torquo -8e, (2E)-torquo-8f, and (2Z)-torquo-8a.