SYNTHESIS AND DEPROTONATION ALKYLATION REACTIONS OF THE CHIRAL CARBENE COMPLEX TP'(CO)(NO)MO=C(OME)(ME)/

The Fischer carbene complex Tp'(CO)(NO)Mo=C(OMe)(Me) (I) has been synt hesized, and functionalization of the carbene methyl substituent has b een achieved via deprotonation/alkylation reaction sequences. The chir al metal center produced moderate diastereoselectivity. Isomeric, geom etric, and thermodynamic features are discussed for the complexes Tp'( CO)(NO)M=C(OMe)(R) (M = W, R = Me; M = Mo, R = Me, Et, Ph, -CH2CH2CH=C H2, -C(H)(Me)CH2CH=CH2) and evidence of a substantial metal carbene ro tational barrier is presented. Important structural features for Tp'(C O)(NO)Mo-C(OMe)(Ph) (7), which was characterized by single-crystal X-r ay crystallography, include a short molybdenum-carbon bond distance to the carbene (2.085(4) Angstrom) and a carbene carbon-oxygen bond dist ance of 1.356(5) Angstrom.