Organic Syntheses via Transition Metal Complexes, 441. - Condensation of Methyl Carbene Complexes with Acid Amides: β-Alkoxyalkenyl- and β-Aminoalkenyl Carbene Complexes of Chromium and Tungsten - Competition of Condensation and Insertion The condensation of the methyl(ethoxycarbene) complexes LnM = C(OEt)CH3 (4) [LnM = Cr(CO)5, W(CO)5] with acid amides RCONR1R2 (5) under the influence of POCl3/Et3N leads stereoselectively to (E)-β-aminoalkenyl(ethoxycarbene) complexes LnM=C(OEt)CH=C(R)NR1R2 [(E)-6] (R = H, aryl, alkyl). A condensation of 4 can also be achieved via amidium salts 11, which are easily available from 5. In this case, (E)-6 and (E)-β-alkoxyalkenyl(ethoxycarbene) complexes LnM=C(OEt)CH = C(R)OEt[(E)-13] were obtained. Via the cyclic amidium salts 15 and 20 four-to seven-membered lactams (E)-17 and (E)-21a-d are accessible. The reaction of 4 with acid amides RCH2CONR1R2 (2) and POCl3/Et3N yields mainly insertion products LnM=C(NR1R2)C(R)=C(OEt)CH3 [(E)/(Z)-22] and only small amounts of condensation products LnM=C(OEt)CH=C(CH2R)NR1R2 [(E)-23].