Immobilized Eosin Y for the Photocatalytic Oxidation of Tetrahydroisoquinolines in Flow

A new easy-to-synthesize solid supported Eosin Y and its application in the building of a catalytic continuous flow reactor is reported. The fluidic device was employed to perform tertiary amines in-flow photooxidations followed by a nucleophile addition, with overall productivity increased by one order magnitude. When using the iminium-ions in situ generated or in a telescoped fashion, the resulting Mannich-products were isolated with high diastereoselectivity and up to 90 % enantioselectivity, simply using air as terminal oxidant.