Catalytic Methylation of C--H Bonds Using CO sub(2) and H sub(2)

Formation of C--C bonds from CO sub(2) is a much sought after reaction in organic synthesis. To date, other than C--H carboxylations using stoichiometric amounts of metals, base, or organometallic reagents, little is known about C--C bond formation. In fact, to the best of our knowledge no catalytic methylation of C--H bonds using CO sub(2) and H sub(2) has been reported. Described herein is the combination of CO sub(2) and H sub(2) for efficient methylation of carbon nucleophiles such as indoles, pyrroles, and electron-rich arenes. Comparison experiments which employ paraformaldehyde show similar reactivity for the CO sub(2)/H sub(2) system.Original Abstract: Ersatz fuer Formaldehyd: Kohlendioxid erweist sich in Gegenwart von H sub(2) als ein effizientes Methylierungsreagens fuer Kohlenstoff-Nukleophile wie 2-substituierte Indole, Pyrrole und elektronenreiche Arene. Experimentelle Daten sprechen fuer einen formalen Abfang von Formaldehyd. acac=Acetylacetonat, triphos=1,1,1-Tris(diphenylphosphanylmethyl)ethan.