Organische Synthesen mit Übergangsmetall-Komplexen, 60. Neuartige Benzoanellierung mit Carben-Komplexen und Alkinen. – 2-Oxybenzoanellierung von Cycloheptatrien über (Cycloheptatrienylmethyl)-carben-Komplexe von Chrom und Wolfram
✍ Scribed by Aumann, Rudolf
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1992
- Tongue
- English
- Weight
- 430 KB
- Volume
- 125
- Category
- Article
- ISSN
- 0009-2940
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✦ Synopsis
Carbene complexes, cycloaddition reactions of 1 Carbene complexes, reactions with alkynes / Benzocycloheptatrienes / 2-Oxybenzoanellation 1 (Cycloheptatrienylmethy1)carbene complexes of chromium and tungsten Organic Syntheses via Transition Metal Complexes, 60r11. -Novel Type of Benzoanellation with Carbene Complexes and Alkynes. -2-Oxybenzoanellation of Cycloheptatriene via (Cycloheptatrienylmethy1)carbene Complexes of Chromium and Tungsten We report on a three-step procedure for the regiospecific 2-L,M = C(NEtz) -C(Me) = C(0Et) -CHzc-C7H7 (3 and 4 resp.). oxybenzoanellation to cycloheptatriene by means of Fischer Thermolysis of 3b [LnM = W(CO)5, 100°C, 5 h] finally leads to carbene complexes and alkynes. The first step involves the elimination of W(CO),(Et,NH) (6b) and the regiospecific forformation of (cycloheptatrienylmethy1)carbene complexes mation of the ethoxybenzocycloheptatrienes 5 7 , and 8 in 92% L,M= C(0Et) -CH2-c-C,H7 (1, L,M = Cr(C0)5 (a), W(CO)5 total yield. The reaction is kinetically controlled and yields (b)] from the corresponding methylcarbene complexes and a an isomeric ratio of 5 : 7 : 8 = 60:12:20% with the thermodytropylium salt. 1 reacts with the alkyne EtzN -C = C -Me (2) namically less stable isomer 5 predominating. to give the (E)and (Z)-1-amino(1-alkeny1)carbene complexes