Octalen-Bicyclo[6.2.0] decapentaen-Umwandlung - via �bergangsmetallkomplexe

Metal-Assisted Cycloaddition Reactions in Organotransition Metal Chemistry

“…Deprotonation of the acidic methyl groups in the cationic [(η 4 -1,1-dimethyltrimethylenemethane)Cp-(CO) 2 W] + complex 389 (eq 102) 625 gives the stable η 3β-isopropenylallyl complex 390 which cycloadds TCNE in A few examples are known where metal-assisted retro-Diels-Alder reactions are used to generate otherwise inaccessible fragments. The intended synthesis of bicyclo[6.2.0]decapentaene 394 by Vogel et al 626 (Scheme 56) was not successful via thermolysis of 392. Heating the solid Fe(CO) 3 complex 393, however, obtained as 2:1 mixture of two stereoisomers, resulted in a clean fragmentation into phthalonitrile and the cyclobutadiene complex from which 394 was readily liberated by oxidative degradation with trimethylamine N-oxide.…”