Dehydrogenative C(sp<sup>3</sup>)–H bond functionalization of tetrahydroisoquinolines mediated by organic oxidants under mild conditions
作者:Zdravko Džambaski、Bojan P. Bondžić
DOI:10.1039/c9ob01090d
日期:——
The organocatalyzed Mannich reaction of unsubstituted and N-aryl-substituted tetrahydroisoquinolines (THIQs) and the Strecker reaction of several N-aryl-substituted THIQs through dehydrogenative C(sp3)-H bond functionalization (cross-dehydrogenative coupling) promoted by organic single electron oxidants DDQ and IBX are presented. The C-H oxidation/Mannich reaction of less reactive N-aryl substituted
A catalytic amount of triarylaminium salt is demonstrated to be an efficient initiator for oxidative Mannich reaction of tertiary amines and nonactivated ketones under mild neutral conditions. Air is essential for this reaction and acts as a terminal oxidant. Metal catalysts, acid or base additives, and stoichiometric amounts of chemical oxidants are all avoided in this methodology. Six examples of
A breath of fresh air: The title reaction has been developed for the coupling of amines with nitroalkanes and different unmodified ketones usingair as the sole oxidant under mild reaction conditions. The safe, convenient, and environmentally benign process, as well as the low catalyst loading, short reaction time, and good yields make this protocol very practical (see scheme).
ruthenium-based magnetically recoverable photoredox nanocatalyst with a large surface area. This visible light harvesting nanocatalyst was effectively used for cross-dehydrogenative coupling via C–H activation between tertiary amines and various carbon nucleophiles with high regioselectivity to afford the C–C coupled products in good to excellent yield using air as an oxidant under ambient conditions. The
Only oxygen and acid! The oxidative coupling of xanthene and other activated benzylic compounds with carbon nucleophiles such as ketones, can be performed under ambient conditions without solvent by simply using oxygen and catalytic amounts of methanesulfonic acid. The proposed reaction mechanism involves substrate activation by formation of hydroperoxides; the method can therefore be regarded as an