Wasserstoffübertragungen, 19. Zur Katalyse von Wasserstoff‐Transfer und 1,5‐H‐Shift durch Rhodium(III)‐chlorid in homogener organischer Phase

Hydrogen Transfer Reactions, 19. — The Catalysis of Hydrogen Transfer and 1,5‐H Shift by Rhodium(III) Chloride in Homogeneous Organic Systems In homogeneous solution, partly in the presence of a phase‐transfer catalyst, rhodium(III) chloride catalyzes the disproportionation of 1,3‐cyclohexadiene and to a lesser extent 1,5‐H shifts. In the start phase the catalyst is reduced to the active monovalent state. In these catalytic systems the dehydrogenation proceeds stereoselectively. – This was shown by tracer experiments and isotopes effects using deuterated 1,3‐cyclohexadienes 1a — d , which were synthesized with high isotopomeric purity.